Efficient fire sprinkler based on liquid nitrogen type low-temperature working medium

Abstract

The invention relates to an efficient fire sprinkler based on liquid nitrogen type low-temperature working media. The efficient fire sprinkler is specially used for new energy battery safety protection. The fire sprinkler is composed of an inner layer and an outer layer, the inner layer is a working medium conveying and forming assembly composed of an inner pipe, an inner head and a conical barrel, the outer layer is a supporting assembly composed of an outer pipe and an outer head, a vacuum heat insulation clamping cavity is formed between the inner layer and the outer layer for cold insulation, and the inner head and the outer head jointly form a prismatic-section nozzle. The core innovation is that a working medium is shaped into a prismatic liquid column by utilizing a prismatic nozzle, the structure induces peripheral edges and corners of jet flow to be vaporized preferentially, an inert air curtain is formed to wrap a central liquid core, radial flash evaporation is effectively delayed, and necking fracture of the liquid column is avoided. According to the technology, the jet flow stability and penetration depth are remarkably improved, ordered and controllable vaporization of the low-temperature working medium is achieved, it is ensured that a deep fire source of the battery pack can be accurately covered, and the fire extinguishing efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of new energy battery safety protection technology, specifically a high-efficiency fire sprinkler head based on liquid nitrogen-based cryogenic working fluid. Background Technology

[0002] Lithium-ion battery thermal runaway fires are a major hidden danger in the fields of new energy vehicles and energy storage. The thermal runaway temperature can reach 800-1000℃, and the suppression effect of traditional fire extinguishing agents (water, foam, dry powder) is limited. Liquid nitrogen (boiling point -196℃) and liquid carbon dioxide (boiling point -78.5℃) are ideal fire extinguishing media. Their mechanism of action lies in the coupling effect of rapid cooling and the construction of an inert environment: rapid heat absorption causes a cliff-like drop in temperature between the fire source center and the surface of combustibles, quickly breaking through the activation energy threshold required for the combustion reaction and cutting off the chain reaction from a thermodynamic perspective; the inert environment inhibits the transfer of residual heat and the oxidation of combustible gases, thereby achieving rapid suppression and prevention of reignition.

[0003] However, traditional atomizing nozzles have the following drawbacks when used with cryogenic working fluids: Traditional nozzles use mechanical structures (swirl channels, fine nozzles, etc.) to break up the liquid jet to promote evaporation. However, the latent heat of vaporization of cryogenic working fluids is relatively low compared to water, and the temperature difference with the environment is large, resulting in extremely rapid vaporization. Mechanical atomization further accelerates vaporization, causing the working fluid to completely vaporize near the nozzle, with the gas phase expanding by hundreds of times. This leads to kinetic energy attenuation and insufficient liquid phase penetration depth, making it difficult to reach the deep parts of the battery pack.

[0004] Traditional nozzles rely on tiny nozzles of 0.5-2mm. During the transport of cryogenic working fluid, a gas-liquid two-phase flow is generated. When the two-phase flow passes through the channel, the high-speed two-phase flow generates a low-temperature effect and ice crystal accumulation in the narrow channel, which can easily cause random blockage.

[0005] Traditional nozzles break up liquid jets through mechanical structures (swirl channels, impact plates, small nozzles, etc.) to rapidly maximize the specific surface area of ​​the working fluid. However, when used with cryogenic working fluids, the temperature field is severely uneven and unpredictable because vaporization and heat absorption occur near the nozzle, making it difficult to create an effective fire extinguishing environment in a timely manner. At the same time, the fire extinguishing working fluid is a cryogenic liquid that vaporizes instantly in the natural environment and expands rapidly in volume. The medium vaporizes as soon as it is sprayed out. Due to the small space inside the battery pack, the liquid nitrogen gas does not have enough time to diffuse rapidly, causing the pressure relief valve to fail to work in time, which can easily cause the battery pack cover to explode. Summary of the Invention

[0006] The purpose of this invention is to provide a high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid to solve the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution.

[0008] A high-efficiency fire sprinkler head based on liquid nitrogen-based cryogenic working fluid includes an outer tube, an outer head, a conical cylinder, an inner tube, and an inner head. The inner head is fixed to one end of the inner tube, and the small-diameter end of the conical cylinder is fixed to the other end of the inner tube. The outer tube is sleeved on the outside of the inner tube, and the outer head is fixed to one end of the outer tube. The large-diameter end of the conical cylinder is fixed to the inner wall of the outer tube on the side away from the outer head. The outer head has an open prismatic structure and forms a prismatic cross-section nozzle with the inner head. The inner tube and the conical cylinder together form a vacuum-insulated cavity with the outer tube. The cross-section of the star-shaped liquid column ejected from the forming nozzle consists of a central circle and n isosceles triangular wedges evenly distributed around the circumference, where n=4-6, and the vertices of the isosceles triangular wedges face outward.

[0009] In one embodiment, after the star-shaped liquid column is ejected, the liquid in the circumferential isosceles triangular wedge-shaped region vaporizes first to form a cryogenic protective layer. The cryogenic protective layer continues to diffuse as the working medium is transported forward, forming an outer protective layer; The cryogenic protective layer and the outer protective layer together form a cryogenic inert gas curtain around the central liquid core at the central sphere.

[0010] Let the radius of the central circle be r, and the height of the isosceles triangular wedge be h, with the ratio of h / r being 0.6-0.9.

[0011] In one embodiment, the cone angle of the conical cylinder is 10°-25°.

[0012] In one embodiment, the outer tube and the inner tube are made of stainless steel or copper alloy.

[0013] In one embodiment, the fire sprinkler head further includes an internally threaded connector connected to the supply pipe; an externally threaded portion matching the internally threaded connector is provided on the outer wall of the outer tube near the end of the conical cylinder; a plurality of clamping elements are evenly distributed in a ring on the outer wall of the outer tube, and the outer tube is also provided with a bladder-type pushing unit; when the internally threaded connector is screwed onto the externally threaded portion on the outer tube, the internally threaded connector and the bladder-type pushing unit are used to drive the clamping elements to swing, so as to form a barbed structure that abuts against the inner wall of the battery box.

[0014] In one embodiment, a plurality of mounting slots are arranged in a ring array on the outer wall of the outer tube, and the clamping members are hinged in the mounting slots one by one; a spring is fixed on the inner wall of the mounting slot, and the other end of the spring is fixed to the clamping member for pulling the clamping member to swing and reset; when the clamping member swings outward and opens until its end abuts against the inner wall of the mounting slot, the clamping member is at the limit position of swing opening; when the clamping member resets to the limit position, it does not extend beyond the outside of the mounting slot.

[0015] In one embodiment, the bladder-type pushing unit includes an annular airbag and an airbag body; each mounting slot is fitted with an airbag body that is pressed and engaged with the clamping member, and the airbag body deforms and expands radially along the outer tube when inflated; an annular flange is integrally formed on the outer wall of the outer tube between the mounting slot and the external thread, and the annular airbag is fixedly fitted on the outer peripheral wall of the annular flange; the thickness of the annular flange is less than the span of the annular airbag along the axial direction of the outer tube, and the fixed connection point between the annular flange and the annular airbag is close to the middle of the inner edge wall of the annular airbag; several air passages are evenly distributed inside the outer tube, one end of the air passage is connected to the airbag body, and the other end passes through the annular flange and is connected to the annular airbag; when the clamping member is reset to the limit position, the airbag body is in a contracted state, and the annular airbag draws back the gas.

[0016] In one embodiment, an extrusion ring that engages with the annular airbag is rotatably mounted at the end of the internally threaded connector.

[0017] In one embodiment, a limiting block is integrally formed on the outer wall of the outer tube.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0019] This invention constructs a high-vacuum insulation jacket structure inside the nozzle by forming a vacuum insulation cavity between the outer and inner tubes. This structure suppresses the radiation and conduction of ambient heat to the low-temperature working fluid in the flow channel, prevents the deep-temperature working fluid from flashing or entering a gas-liquid two-phase flow state inside the nozzle, and ensures the liquid phase continuity and initial kinetic energy of the outlet jet.

[0020] This invention utilizes a shaped nozzle consisting of an outer and inner head to shape the working fluid into a prismatic liquid column. The prismatic cross-section structure induces the outer periphery of the jet to break up and rapidly vaporize first. The angular region vaporizes and forms an inert gas curtain, which envelops and shields the central liquid core, slowing down the radial flash rate of the central liquid core. The prismatic column structure suppresses low-order necking modes, avoiding long-wavelength axisymmetric necking and random fracture of the liquid column. The stability of the jet structure is greatly improved, effectively increasing the penetration depth of the liquid phase core, meeting the coverage requirements of deep fire sources in the battery pack, and realizing rapid replacement of oxygen-containing air and the construction of an inert environment. At the same time, it ensures that the gas phase diffusion process matches the liquid phase propulsion rate, avoiding the risk of shell explosion caused by sudden local pressure rise.

[0021] The flow channel in this invention has no throttling parts formed by tiny nozzles, and the diameter is much larger than that of traditional atomizing nozzles. Even if the cryogenic working fluid carries a gas phase, it can pass through smoothly, eliminating the problems of local temperature drop and blockage caused by the accumulation of ice crystals and dry ice.

[0022] This invention utilizes a gas transfer linkage design in a bladder-type pushing unit. When the internal threaded connector is screwed onto the external threaded part, the clamping part is driven to swing outward to form a hook-shaped clamping structure, achieving synchronous locking between the nozzle body and the inner and outer walls of the battery box. At the same time, after the annular airbag is compressed and deformed, it forms a sealed filling of the gap between the end of the internal threaded connector and the outer wall of the battery box. This structure allows the nozzle to be installed, disassembled, and maintained from the outside without disassembling the battery pack. Attached Figure Description

[0023] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the present invention; Figure 2 for Figure 1 One of the partial cross-sectional schematic diagrams of the structure shown; Figure 3 This is a schematic diagram of the cross-section of the star-shaped liquid column ejected by this nozzle; Figure 4 This is a schematic diagram illustrating the vaporization process of a star-shaped liquid column. Figure 5 This is a schematic diagram of a partial structure on the outer tube; Figure 6 For Figure 1 The second partial cross-sectional schematic diagram of the structure shown; Figure 7 for Figure 6 Enlarged schematic diagram of the structure at point A in the middle; Figure 8 This is a schematic diagram of the cross-sectional structure of an internal threaded connector; Figure 9 This is a schematic diagram of the structure of the fire sprinkler installed on the battery box.

[0024] In the diagram: 01, central circle; 02, isosceles triangular wedge; 03, low-temperature protective layer; 04, outer protective layer; 05, battery box; 051, mounting hole; 052, limiting slot; 1, vacuum insulation cavity; 2, outer tube; 201, limiting block; 21, mounting slot; 3, outer head; 4, conical cylinder; 5, inner tube; 6, inner head; 61, forming nozzle; 7, annular airbag; 71, annular flange; 72, air passage; 73, airbag body; 8, clamping component; 81, spring; 82, ball bearing; 9, internal threaded connector; 91, supply pipe; 92, extrusion ring. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the embodiments: This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0026] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Please see Figures 1-9 The present invention provides a high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid, the fire sprinkler head including an outer tube 2, an outer head 3, a conical cylinder 4, an inner tube 5, and an inner head 6. Example 1

[0029] The outer tube 2 is made of 304 stainless steel seamless steel pipe with an inner diameter of 35mm, a wall thickness of 8mm, and a length of 135mm. The outer tube 2 has a circular cross-section to provide rigid support for the outer head 3.

[0030] The outer head 3 is made of 304 stainless steel and has an open prismatic structure with a length of 20mm. The interior of the outer head 3 has a hexagonal cross-section channel, and the corners of the outer head 3 are rounded with a radius of 2mm to reduce stress concentration.

[0031] The conical cylinder 4 is integrally machined from 304 stainless steel and has a hollow conical structure. The outer diameter of the large end of the conical cylinder 4 is about 35mm, which matches the inner diameter of the outer tube 2. The inner diameter of the small end of the conical cylinder 4 is 20mm, the cone angle is 21°, the length is 30mm, and the wall thickness is 2mm. The inner wall of the conical cylinder 4 is a smooth conical surface with a surface roughness Ra<0.4μm, which is used to achieve a smooth transition of the pipe diameter and avoid local throttling and turbulence during the transport of the working medium.

[0032] The inner tube 5 is made of seamless 304 stainless steel pipe with an inner diameter of 20mm, a wall thickness of 2mm, and a length of 80mm. The inner wall of the inner tube 5 is precision polished with a surface roughness Ra<0.8μm to reduce the flow resistance and heat exchange between the working fluid and the pipe wall. The inner tube 5 is a straight pipe with a constant diameter, without diameter change or throttling components, ensuring that the low-temperature working fluid is delivered to the nozzle outlet in a stable liquid phase.

[0033] The inner head 6 is made of 304 stainless steel and is 20mm long with a wall thickness of 2mm. One end of the inner head 6 is a circle that matches the inner tube 5, and the other end is a hexagonal structure that matches the conical cylinder 4. It provides liquid phase forming guidance for the low-temperature working fluid and ensures that the liquid working fluid is ejected in a stable prismatic column shape.

[0034] The inner head 6 is welded and fixed to one end of the inner tube 5, and the small diameter end of the conical cylinder 4 is welded and fixed to the other end of the inner tube 5. The outer tube 2 is sleeved on the outside of the inner tube 5, and the outer head 3 is welded and fixed to one end of the outer tube 2. The large diameter end of the conical cylinder 4 is welded and fixed to the side of the inner wall of the outer tube 2 away from the outer head 3. The outer head 3 and the inner head 6 form a prism-shaped nozzle 61 for the fire-fighting medium to be sprayed out.

[0035] like Figure 2 As shown, the inner tube 5 and the conical cylinder 4 together form a vacuum insulation cavity 1 with the outer tube 2. During the assembly process, the outer tube 2 and the outer head 3 are first welded into unit A, and the conical cylinder 4, the inner tube 5 and the inner head 6 are welded into unit B. Then, unit B is inserted into unit A and welded together, forming a vacuum insulation cavity 1. Finally, the vacuum insulation cavity 1 is evacuated to a pressure not exceeding 0.5 Pa through the vacuum extraction nozzle on the outer tube 2, and the extraction nozzle is sealed. This creates a vacuum insulation environment in the vacuum insulation cavity 1, blocking the transfer of ambient heat to the nozzle and delaying the premature vaporization of the working fluid during transport. In addition, each weld is subjected to radiographic testing after welding to ensure sealing. A vacuum replenishment interface is reserved on the nozzle body to ensure that the vacuum level in the vacuum insulation cavity 1 can be maintained for a long time.

[0036] In addition, a composite insulation structure of multiple layers of aluminum foil and glass fiber paper is added inside the vacuum insulation cavity 1 to further enhance the insulation effect.

[0037] like Figure 3 As shown, the cross-section of the star-shaped liquid column ejected from the forming nozzle 61 consists of a central circular body 01 and six circumferentially distributed isosceles triangular wedges 02, i.e., n=6. The base of the isosceles triangular wedges 02 is externally or internally tangent to the outer circumference of the central circular body 01, and the vertices of the isosceles triangular wedges 02 face outward. The radius of the central circular body 01 is r=10mm, the height h of the isosceles triangular wedges 02 is approximately 8.7mm, and h / r=0.87.

[0038] Taking a battery pack with dimensions of 1131mm×793mm×240mm as an example, four lithium-ion battery modules are arranged inside. The nozzle manufactured in this embodiment is installed inside the battery pack, triggering thermal runaway of the intermediate battery module. The ambient temperature is 25℃, liquid nitrogen is used as the extinguishing medium, and the nozzle inlet pressure is 0.8MPa. When the nozzle is working, under ideal conditions, the measured liquid phase penetration depth can stably exceed 800mm, meeting the deep fire source coverage requirements of most battery packs. At the same time, the circumferential oxygen concentration drops below 15% within 5 seconds, and the battery pack structure remains intact without damage. Example 2

[0039] The difference between this embodiment and Embodiment 1 is that: The outer head 3 and inner head 6 are pentagonal structures, that is, the number of isosceles triangular straight wedges 02 is n=5. At the same time, the dimensions of the corresponding parts are adjusted so that the radius of the central circle 01 is r=10mm, the height of the isosceles triangular straight wedge 02 is h=8mm, and h / r=0.8.

[0040] Taking a size of 1131mm×793mm×240mm as an example, four sets of lithium-ion battery modules are arranged inside. The nozzle manufactured in this embodiment is installed in the battery pack, triggering thermal runaway of the intermediate module. The ambient temperature is 25℃, and it is directly supplied by a low-pressure liquid carbon dioxide storage tank (2-3MPa, around -20℃). When the nozzle is working, the liquid phase penetration depth is measured to be 600mm, which meets the usage requirements and is suitable for scenarios where liquid carbon dioxide is used as the extinguishing medium.

[0041] The working principle of this fire sprinkler head is as follows: The cryogenic working fluid is supplied from the external pipeline and first flows through the conical cylinder 4. The tapered gradual structure of the conical cylinder 4 achieves a smooth transition from large to small pipe diameter, avoiding the local throttling and eddies generated by traditional variable diameter structures, and reducing the probability of gas-liquid two-phase flow formation. The working fluid then enters the inner pipe 5. The smooth structure of the inner pipe 5 with constant diameter ensures that the working fluid is transported forward in a stable liquid phase state. During this process, the vacuum insulation cavity 1 between the outer pipe 2 and the inner pipe 5 can effectively block the transfer of ambient heat to the internal working fluid, and the working fluid on the wall vaporizes in advance during the transportation process.

[0042] When the liquid working fluid is ejected from the forming nozzle 61, the circular liquid flow is shaped into a prismatic cross section. The vaporization process of this star-shaped liquid column is a gradient vaporization, which utilizes the physical property that the high curvature of the edges makes it easy to vaporize, while the low curvature of the center makes it difficult to vaporize. It is completed in the following stages: Preliminary experiments showed that after the prismatic liquid column was ejected, the circumferential isosceles triangular wedge 02 came into rapid contact with room temperature air, and the geometric change induced local turbulence, which destroyed the stability of the thermal boundary layer and promoted vaporization. The vaporized body at the sharp corner rapidly merges with the vaporized bodies on the two isosceles lateral sides of the isosceles triangular right wedge 02, as... Figure 4 As shown, a low-temperature inert and dense low-temperature protective layer 03 is formed around the prismatic liquid column, with a temperature of approximately -100℃ to -50℃, forming a stable encapsulating inert environment and delaying the vaporization of the central circular body 01 region. As the working fluid is transported forward, the cryogenic protective layer 03 continues to diffuse circumferentially, forming an outer protective layer 04. Due to the vaporization and expansion of the cryogenic working fluid by hundreds of times, the cryogenic protective layer 03 and the outer protective layer 04 diffuse outward at a high pressure of 0.05-0.1 MPa, forming a cryogenic inert gas curtain with a diameter of 500-800 mm. This gas curtain enables the rapid replacement of the original oxygen-containing air in the battery pack, and the oxygen concentration can be reduced to below 15% within 5-10 seconds, thereby forming an inert gas protective layer. Under the shielding of the aforementioned inert gas protective layer, the central circular body 01 is only in contact with a small amount of low-temperature gaseous medium, which greatly slows down the vaporization rate. As a result, the central circular body 01 can maintain a stable forward transport of the liquid phase nucleus and achieve deep liquid phase penetration. Due to the large radius of curvature of the central circular body 01 and its surrounding by the low-temperature inert gas curtain, the vaporization rate of the central liquid core is reduced to 30%-50% of the conventional value, thereby ensuring that the liquid phase nucleus can penetrate to the depth of the battery pack. During the transport process, the inert gas protective layer formed at the isosceles triangular wedge 02 gradually becomes rounded at the sharp corners and gradually decreases in volume until it disappears completely due to continuous vaporization. After reaching the deep part of the battery pack target, the liquid phase nucleus at the isosceles triangular wedge 02 gradually vaporizes as the protective layer dissipates. The latent heat of vaporization of the liquid phase nucleus is concentrated and released at the center of the fire source, achieving precise cooling and fire extinguishing.

[0043] Traditional circular liquid columns, under the influence of surface tension, are dominated by Rayleigh-Platto instability, leading to thinning and random breakage. Preliminary experiments show that the present invention, through the circumferential disturbance introduced by the prismatic cross-section, suppresses axisymmetric necking fracture of the jet and avoids random breakage of the liquid column. Under the same working conditions, it can reduce the fluctuation range of the stable length of the jet by more than 80%, improve the consistency and controllability of the jet penetration depth, and achieve more than three times the improvement compared to traditional circular liquid columns.

[0044] The minimum nozzle diameter of this fire sprinkler is much larger than the 0.5-2mm nozzle diameter of traditional sprinklers, which avoids sudden drops in local temperature and prevents the accumulation of ice crystals or dry ice. The smooth, uniform diameter straight pipe structure results in a low flow resistance coefficient for gas-liquid two-phase flow, significantly reducing flow resistance and local throttling temperature drop.

[0045] An open prismatic channel is formed by the outer head 3 and the inner head 6, without any closed channels or throttling components. The vaporized gas phase can expand freely and release pressure uniformly along the jet direction. The gas phase expansion rate matches the liquid phase propulsion rate, avoiding sudden increases in local pressure within the battery pack. This ensures that the gas phase release and pressure relief capacity within the battery pack are matched, preventing the battery pack from exploding. Example 3

[0046] Please see Figures 5-9 This fire sprinkler is also equipped with an internal threaded connector 9 that connects to the supply pipe 91; the outer wall of the outer pipe 2 is provided with an external threaded part that matches the internal threaded connector 9 at one end near the conical cylinder 4; four clamping parts 8 are evenly distributed in a ring on the outer wall of the outer pipe 2. The clamping parts 8 are long strips. The outer pipe 2 is also provided with a bladder-type pushing unit; when the internal threaded connector 9 is screwed onto the external threaded part on the outer pipe 2, the internal threaded connector 9 and the bladder-type pushing unit are used to drive the clamping parts 8 to swing, so as to form a hook-shaped structure that abuts against the inner wall of the battery box 05.

[0047] The outer tube 2 has four mounting slots 21 arranged in a ring on its outer wall. The clamping parts 8 are hinged to each other in the mounting slots 21. A spring 81 is fixed on the inner wall of the mounting slot 21, and the other end of the spring 81 is fixed to the clamping part 8. The spring 81 is used to pull the clamping part 8 to swing back to its original position. When the clamping part 8 swings outward and opens until its end abuts against the inner wall of the mounting slot 21, the clamping part 8 is at the limit position of swinging open. When the clamping part 8 returns to the limit position, it does not extend beyond the outside of the mounting slot 21, so as to avoid the clamping part 8 from protruding too much and affecting the installation.

[0048] The bladder-type pushing unit includes an annular air bladder 7 and an air bladder body 73; each mounting groove 21 is fitted with an air bladder body 73 that is pressed and cooperated with the clamping member 8, and the air bladder body 73 deforms and expands radially along the outer tube 2 when inflated. The contact width between the air bladder body 73 and the clamping member 8 is not less than 4mm and not less than 60% of the width of the clamping member, ensuring that a stable and effective pressing effect can be formed between the two.

[0049] An annular flange 71 is integrally formed on the outer wall of the outer tube 2 between the mounting groove 21 and the external thread. The annular airbag 7 is fixedly fitted on the outer peripheral wall of the annular flange 71. The thickness of the annular flange 71 is less than the span of the annular airbag 7 along the axial direction of the outer tube 2, and the fixed connection point between the annular flange 71 and the annular airbag 7 is close to the middle of the inner edge wall of the annular airbag 7. This ensures that the annular airbag 7 can deform under pressure on both sides.

[0050] Four air passages 72 are evenly distributed inside the outer tube 2. One end of the air passage 72 is connected to the airbag body 73, and the other end passes through the annular flange body 71 and is connected to the annular airbag 7. When the clamping member 8 is reset to the limit position, the airbag body 73 is in a contracted state, and the annular airbag 7 draws back the gas.

[0051] Among them, the airbag body 73 and the ring airbag 7 are made of special formulas such as methyl phenyl silicone rubber or fluorosilicone rubber, which can maintain elasticity in a certain range of low temperature environments.

[0052] When this fire sprinkler is installed, the internal threaded connector 9 is separated from the outer tube 2, and the annular airbag 7 is not compressed. Therefore, the clamping part 8 is repositioned in the mounting groove 21 under the restraint of the spring 81. Then, the outer tube 2 is inserted into the mounting hole 051 on the battery box 05 to ensure that each clamping part 8 enters the battery box 05. Subsequently, the internal threaded connector 9 is screwed onto the external thread of the outer tube 2. As the internal threaded connector 9 is continuously tightened, it will compress the annular airbag 7. After the annular airbag 7 is compressed, the gas inside it flows into the airbag body 73 through the air passage 72, causing the airbag body 73 to expand and extend radially along the outer tube 2. At this time, the airbag body 73 will push the clamping member 8 to overcome the elastic force of the spring 81 and swing outward (the spring 81 is stretched and stored). As the pressure on the annular airbag 7 intensifies, the swing amplitude of the clamping member 8 also increases. When the clamping part 8 swings open into a hook shape, it abuts against the inner wall of the battery box 05. As the internal threaded connector 9 continues to tighten, the nozzle body moves outward, and the swing angle of the clamping part 8 continues to increase until the end of the clamping part 8 located in the mounting groove 21 abuts against the inner wall of the mounting groove 21, at which point the clamping part 8 opens to its maximum angle. When the internal threaded connector 9 is screwed to its limit position, its end abuts against the outer wall of the battery box 05, and the outer end of the clamping member 8 abuts against the inner wall of the battery box 05. The two sides work together to lock the nozzle, thus fixing the nozzle as a whole. Then, the supply pipe 91 is connected to the internal threaded connector 9. In this way, the supply pipe 91 is connected to the inner pipe 5, and the fire sprinkler head is fixed to the battery box 05 at the same time, achieving two goals at once.

[0053] In addition, after the nozzle is installed in place, one side of the annular airbag 7 is squeezed by the outer wall of the battery box 05, and the other side is squeezed by the end of the internal threaded connector 9. The annular airbag 7 is under high pressure, which can completely fill the gap between the end of the internal threaded connector 9 and the outer wall of the battery box 05, thus achieving a sealing effect.

[0054] When disassembling and maintaining this fire sprinkler head, unscrew the internal threaded connector 9 from the outer tube 2 to release the pressure on the annular airbag 7. Under the combined action of the annular airbag 7 deforming and resetting to draw back the gas from the airbag body 73 and the elastic force of the spring 81, the clamping part 8 will swing in the opposite direction until the clamping part 8 is completely reset into the mounting groove 21. Then, the sprinkler head body can be pulled out from the mounting through hole 051. It can be seen that this sprinkler head can be quickly disassembled and installed from the outside without disassembling the battery pack.

[0055] like Figure 8 and Figure 9 As shown, the end of the internal threaded connector 9 is rotatably mounted with a compression ring 92 that abuts against the annular airbag 7. When the compression ring 92 abuts against the annular airbag 7, the compression ring 92 in contact with the annular airbag 7 will not rotate synchronously with the internal threaded connector 9, thus avoiding excessive wear on the annular airbag 7.

[0056] like Figure 5 As shown, a limit block 201 is integrally formed on the outer wall of the outer tube 2. Furthermore, as... Figure 9 As shown, a limiting slot 052 matching the limiting block 201 is provided on the inner wall of the mounting hole 051. When the nozzle body is inserted into the mounting hole 051, the limiting block 201 is aligned and slides into the limiting slot 052 to achieve a positioning effect, preventing the nozzle body from rotating synchronously when the internal threaded connector 9 is tightened, thus facilitating the installation and removal of the nozzle.

[0057] In addition, such as Figure 7 and Figure 9 As shown, a ball bearing 82 is also embedded at the end of the clamping member 8. The ball bearing 82 makes rolling contact with the inner wall of the battery box 05 to ensure the smoothness of the clamping member 8 when it swings.

[0058] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

Claims

1. A high-efficiency fire sprinkler head based on liquid nitrogen-based cryogenic working fluid, characterized in that: It includes an outer tube (2), an outer head (3), a conical cylinder (4), an inner tube (5), and an inner head (6); The inner head (6) is fixed to one end of the inner tube (5), and the small diameter end of the conical cylinder (4) is fixed to the other end of the inner tube (5); The outer tube (2) is sleeved on the outside of the inner tube (5), the outer head (3) is fixed to one end of the outer tube (2), and the large diameter end of the conical cylinder (4) is fixed to the side of the inner wall of the outer tube (2) away from the outer head (3). The outer head (3) is an open prismatic structure and forms a prismatic cross-section shaped nozzle (61) with the inner head (6). The inner tube (5) and the conical cylinder (4) together form a vacuum insulation cavity (1) with the outer tube (2). The cross section of the star-shaped liquid column ejected from the forming nozzle (61) consists of a central circle (01) and n isosceles triangular straight wedges (02) evenly distributed around the circumference; Where n=4-6, the vertex of the isosceles triangular wedge (02) faces outward.

2. The high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 1, characterized in that: After the star-shaped liquid column is ejected, the liquid in the circumferential isosceles triangular wedge-shaped area (02) vaporizes first to form a low-temperature protective layer (03). The low-temperature protective layer (03) continues to diffuse as the working medium is transported forward, forming an outer protective layer (04). The low-temperature protective layer (03) and the outer protective layer (04) together form a low-temperature inert gas curtain around the central liquid core at the central sphere (01).

3. The high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 1, characterized in that: Define the radius of the central circle (01) as r, the height of the isosceles triangular wedge (02) as h, and the ratio of h / r as 0.6-0.

9.

4. The high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 1, characterized in that: The cone angle of the conical cylinder (4) is 10°-25°.

5. A high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 1, characterized in that: The outer tube (2) and inner tube (5) are made of stainless steel or copper alloy.

6. A high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 1, characterized in that: It also includes an internal threaded connector (9) that connects to the supply pipe (91); The outer tube (2) has an external threaded part on the outer edge wall near the conical cylinder (4) that matches the internal threaded connector (9); The outer tube (2) has several clamping parts (8) evenly distributed in a ring on its outer wall, and the outer tube (2) is also provided with a bladder-type pushing unit; When the internal threaded connector (9) is screwed onto the external threaded part of the outer tube (2), the internal threaded connector (9) is used in conjunction with the bladder-type pushing unit to drive the clamping part (8) to swing, so as to form a hook-shaped structure that abuts against the inner wall of the battery box (05).

7. A high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 6, characterized in that: The outer tube (2) has several mounting slots (21) arranged in a ring array on its outer wall, and the clamping parts (8) are hinged in the mounting slots (21) one by one. A spring (81) is fixed on the inner wall of the mounting groove (21), and the other end of the spring (81) is fixed to the clamping member (8) for pulling the clamping member (8) to swing and reset. When the clamping member (8) swings outward and opens until its end abuts against the inner wall of the mounting groove (21), the clamping member (8) is at the limit position of swing opening; When the clamping member (8) is reset to the limit position, it does not extend beyond the outside of the mounting groove (21).

8. A high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 7, characterized in that: The bladder-type pushing unit includes an annular airbag (7) and an airbag body (73); Each of the mounting slots (21) is fitted with an airbag body (73) that is pressed and engaged with the clamping member (8), and the airbag body (73) expands radially along the outer tube (2) when inflated; An annular flange (71) is integrally formed on the outer wall of the outer tube (2) between the mounting groove (21) and the external thread. The annular airbag (7) is fixedly fitted on the outer peripheral wall of the annular flange (71). The thickness of the annular flange (71) is less than the span of the annular airbag (7) along the axial direction of the outer tube (2), and the fixed connection point between the annular flange (71) and the annular airbag (7) is close to the middle of the inner edge wall of the annular airbag (7). The outer tube (2) is evenly distributed with several air passages (72). One end of each air passage (72) is connected to the airbag body (73), and the other end passes through the annular flange body (71) and is connected to the annular airbag (7). When the clamping part (8) is reset to the limit position, the airbag body (73) is in a contracted state, and the annular airbag (7) draws back the gas.

9. A high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 6, characterized in that: The end of the internal threaded connector (9) is rotatably fitted with a compression ring (92) that abuts against the annular airbag (7).

10. A high-efficiency fire sprinkler head based on liquid nitrogen cryogenic working fluid according to claim 6, characterized in that: The outer tube (2) has an integrally formed limit block (201) on its outer wall.

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