Flame retardant property test box for cable flame retardant material
By designing a cable flame retardant performance test chamber and adopting a simulated fire environment with multiple fire sources and adjustable gas, the problem of frequent inspections in the design of cable flame retardant materials is solved, an efficient and economical verification method is achieved, the testing cost is reduced, and the design efficiency is improved.
Patent Information
- Application Number
- CN202422548444.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-09-23
- Estimated Expiration
- 2034-10-22
AI Technical Summary
In the existing technology, during the design process of cable flame retardant materials, frequent inspections make it difficult to timely feed back the test results into the design process, increasing the testing cost and lacking efficient and widely applicable verification methods.
A cable flame retardant performance test chamber is designed, which includes a fire-resistant chamber, a sample rack, multiple fire sources, a gas inlet, a sensor and an exhaust port. An adjustable mixed gas ratio and a retractable flame nozzle are used to simulate the actual fire environment for multiple tests.
By simulating the actual fire environment, it provides an efficient and economical means of verifying cable flame retardant materials, reduces the number of inspections, reduces testing costs, and improves the efficiency of the design process.
Smart Images
Figure CN223377277U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of cable material testing, in particular to a flame retardant performance test box for cable flame retardant materials. Background Art
[0002] A cable's flame retardancy is one of its combustion properties. Based on various standards, cable combustion properties can be categorized as flame retardant, fire-resistant, halogen-free, low-smoke, and low-toxic. A flame-retardant cable is one that, under specified test conditions, after the ignition source is removed, the flame spreads only within a limited range, and any residual flames or burns self-extinguish within a specified timeframe.
[0003] Generally speaking, because the metal materials that make up cables are naturally nonflammable, a cable's flame retardancy is more closely related to the polymer materials in its structure (such as insulation and sheathing). The flame retardancy of cable materials is a mandatory performance requirement for safety regulations, typically referring to the ability of flame-retardant materials to inhibit or delay combustion without themselves being prone to combustion.
[0004] Flame-retardant cable materials must be certified for flame retardancy by a qualified testing agency before they can be sold and used. During the design process, multiple evaluations and verifications are required to ensure the design meets flame retardancy standards. Currently, multiple batches of cable flame-retardant materials are submitted for testing during the design process, with the material formulation adjusted based on the test results until qualified. Frequent testing makes it difficult to promptly incorporate test results into the design process, increasing testing costs.
[0005] How to provide efficient and widely applicable verification methods during the design stage of cable flame retardant materials is a technical problem that needs to be solved. Summary of the Invention
[0006] In order to solve the above problems existing in the prior art, the utility model proposes a flame retardant performance test box for cable flame retardant materials, which includes a fire-resistant box body in which a sample rack, a fire source, a gas inlet, a sensor and an exhaust port are installed.
[0007] The box body is connected to a door that can be opened and closed, and the door has a sealing structure; the side wall of the box body is connected to an observation window;
[0008] Each wall of the box body is a three-layer structure, which is a ceramic layer, an asbestos layer and a steel plate layer from the inside to the outside. The box body is installed on a bracket with the bottom suspended in the air.
[0009] The sample rack is located in the center of the cavity in the box body, and has a sample placement area on the sample rack; the structure of the sample rack includes two pairs of clamping blocks, and the sample placement area is between the two pairs of clamping blocks, and the sample placement area is in the shape of a flat plate; the inner wall of each pair of clamping blocks has a ceramic layer;
[0010] There are multiple fire sources, and the flame nozzles of the fire sources are connected to the combustion gas source through a fuel pipeline; each flame nozzle faces the sample placement area; for any flame nozzle, it has an independent fuel pipeline and ignition device; the air inlet of the fuel pipeline is connected to the air outlet of a mixed gas source of combustible gas (such as propane gas) and oxygen, and the ratio of the two gases in the mixed gas source is adjustable; (the gas required for the combustion of the fire source is ensured, and the gas required for the combustion of the fire source and the impact of the generated gas on the judgment of the flame retardant performance of the cable material are minimized. At the same time, the amount of gas required for the combustion of the fire source and the generated gas can be calculated).
[0011] The gas inlet is located on the bottom surface of the box below the sample placement area, and the gas inlet is connected to a mixed gas source of nitrogen, carbon dioxide and oxygen; the ratio of the three gases in the mixed gas source is adjustable; (ensuring that the ratio and volume of the gases in the box used to affect the combustion / flame retardancy of the cable material are controllable. At the same time, in extreme emergency situations, the oxygen can be turned off and nitrogen and carbon dioxide can be used to extinguish the fire in the box).
[0012] The exhaust port is located on the top surface of the box above the sample placement area, and a gas collecting hopper is connected above the exhaust port. The gas outlet of the gas collecting hopper is connected to the smoke concentration detection channel through an air pipe, and the gas outlet of the smoke concentration detection channel is connected to the air pipe; the inner cavity of the gas collecting hopper is in the shape of a trumpet with a large air inlet and a small air outlet; the inner cavity of the smoke concentration detection channel is in the shape of a cylinder, and the diameter of the cylinder is larger than the diameter of the air pipes at both ends thereof; a smoke concentration sensor is arranged in the middle position of the smoke concentration detection channel;
[0013] Install a toxic gas sensor in the gas collecting hopper;
[0014] A plurality of thermocouples are installed in the box, and each thermocouple is divided into a plurality of groups, and the distance between each group of thermocouples and the sample placement area is the same.
[0015] Furthermore, there are two groups of flame nozzles, which are respectively located at the upper and lower sides of the sample placement area;
[0016] Each set of flame nozzles consists of multiple nozzles, their axes perpendicular to the sample placement area, forming a matrix. Each nozzle is connected to the inner wall of the chamber via a retractable mechanism. The upper and lower sets of flame nozzles each perform flame combustion on a flat-plate material sample.
[0017] Furthermore, the door is located at the center of the top of the box; the exhaust port is located on the door, and the air inlet of the air collecting hopper is connected to the exhaust port through a sealing structure; the clamping block is connected to the inner side of the door through a connecting rod.
[0018] (In this example, the door is the entire top plate of the box, and the thermocouples distributed on the top surface of the box are installed on the bottom surface of the door. The four sides of the door of this structure are connected to the four sides of the box by locks, which is conducive to the sealing effect of the sealing structure.)
[0019] Furthermore, the telescopic mechanism is a telescopic sleeve made of metal; the inner and outer sleeves of the telescopic sleeve are limited by fastening screws.
[0020] Furthermore, the gas source of the combustible gas and the gas source of the air are connected to the air inlet of the fuel pipeline through a mixed gas valve.
[0021] Furthermore, the nitrogen, carbon dioxide, and oxygen sources are each connected to the inlet of the four-way pipe, and the outlet of the four-way pipe is connected to the gas inlet. Each of the three inlet ports of the four-way pipe has a valve. The nitrogen, carbon dioxide, and oxygen sources are all at normal pressure (consistent with atmospheric pressure). Under normal pressure, the combustion-supporting and flame-retardant gases have no additional impact on the flame retardancy of the cable material, ensuring that the flame retardancy of the cable material is as close to actual operating conditions as possible.
[0022] Furthermore, a transition duct connects the air inlet of the smoke concentration detection channel to the pipeline. The air inlet of the transition duct is the same as the air outlet of the pipeline and the air inlet of the smoke concentration detection channel. The inner cavity of the transition duct is truncated cone-shaped (to prevent a sudden decrease in gas pressure, which would cause large smoke particles in the smoke to fall and affect the detection effect).
[0023] During the development and trial production phase of cables and cable materials, this test chamber can be used to perform flame retardancy tests on cables and cable materials multiple times and economically. The structure of this test chamber makes the flame retardancy test as close as possible to the fire environment in actual use. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a schematic diagram of the structure of the test box of this embodiment (perspective)
[0025] Figure 2 This is a schematic diagram of the structure of the sample placement area of this embodiment ( Figure 1 Right perspective)
[0026] Figure 3 It is a schematic diagram of the combustion gas source principle of the fire source;
[0027] Figure 4 This is a schematic diagram of the gas source principle of the gas inlet;
[0028] Figure 5 1 is a schematic diagram of an axial cross section of a smoke concentration detection channel;
[0029] In the figure, the box 1, the sample rack 2, the telescopic sleeve 3, the sample placement area 4, the exhaust port 5, the door 6, the ceramic layer 7, the asbestos layer 8, the steel plate layer 9, the bracket 10, the transition duct 11, the flame nozzle 12, the fuel pipeline 13, the gas inlet 17, the gas collecting hopper 18, the flue gas concentration detection channel 19, the flue gas concentration sensor 20, the toxic gas sensor 21, the thermocouple 22, the clamp 23, the ceramic block 24, the connecting rod 25, the lock 26, the mixed gas valve 27, the four-way pipeline 28, the propane gas source 29, the air source 30, the nitrogen source 31, the carbon dioxide source 32, and the oxygen source 33. DETAILED DESCRIPTION
[0030] The present invention will be further described below with reference to the accompanying drawings and specific implementation methods.
[0031] refer to Figure 1 A flame retardant performance test box for cable flame retardant materials includes a fire-resistant box body 1, in which a sample rack 2, a fire source, a gas inlet 17, a sensor and an exhaust port 5 are installed.
[0032] The box body 1 is connected to a door 6 that can be opened and closed, and a sealing structure (such as a heat-resistant sealing strip) is provided on the door; an observation window is connected to the side wall of the box body;
[0033] Each wall of the box body 1 is a three-layer structure, which is a ceramic layer 7, an asbestos layer 8 and a steel plate layer 9 from the inside to the outside. The box body is installed on a bracket 10, and the bottom is suspended.
[0034] The sample rack 2 is located in the center of the cavity in the box body, and there is a sample placement area 4 on the sample rack, which is in the shape of a flat plate;
[0035] There are multiple fire sources, all of which are flame nozzles 12 connected to a combustion gas source via fuel pipes; each flame nozzle faces the sample placement area 4; each flame nozzle is connected to the inner wall of the box via a retractable mechanism; each flame nozzle has an independent fuel pipe and ignition device (e.g., a pulse igniter); the air inlet of the fuel pipe is connected to a mixture of combustible gas (e.g., propane gas) and oxygen, and the ratio of the two gases in the mixture is adjustable;
[0036] The gas inlet 17 is located on the bottom surface of the box below the sample placement area 4, and the gas inlet is connected to a mixed gas of nitrogen, carbon dioxide and oxygen; the ratio of the three gases in the mixed gas is adjustable;
[0037] The exhaust port 5 is located on the top surface of the box above the sample placement area 4, and an air collecting hopper 18 is connected above the exhaust port. The air outlet of the air collecting hopper is connected to the smoke concentration detection channel 19 through the air pipe, and the air outlet of the smoke concentration detection channel is connected to the air pipe; the inner cavity of the air collecting hopper is a trumpet shape with a large air inlet and a small air outlet; the inner cavity of the smoke concentration detection channel 19 is cylindrical, and the diameter of the cylinder is larger than the diameter of the air pipes at both ends.
[0038] The above sensors include three types: smoke concentration sensor 20, toxic gas sensor 21, and thermocouple 22. (For further reference, Figure 5 ) A flue gas concentration sensor 20 is arranged in the middle position of the flue gas concentration detection channel; a toxic gas sensor 21 is installed in the gas collecting hopper 18; and multiple thermocouples 22 are installed in the box. The thermocouples are divided into multiple groups, and the distance between each thermocouple in each group and the sample placement area is the same.
[0039] In this example:
[0040] Further references Figure 2 The structure of the sample holder 2 includes two pairs of clamping blocks 23, and the inner wall of each pair of clamping blocks has a ceramic layer (the ceramic layer is composed of multiple ceramic blocks 24).
[0041] The door is located at the center of the top of the box; the exhaust port 5 is located on the door, and the air inlet of the air collecting hopper is connected to the exhaust port through a sealing structure; the clamping block is connected to the inner side of the door through a connecting rod 25. Figure 1 In this example, the door is the entire top plate of the box, and the thermocouples distributed on the top surface of the box are installed on the bottom surface of the door. The four sides of the door of this structure are connected to the four sides of the box through locks 26, which is beneficial to the sealing effect of the sealing structure.
[0042] Further references Figure 2 There are two groups of flame nozzles 12, and the two groups of flame nozzles are respectively located on the upper and lower sides of the sample placement area 4;
[0043] In each group of flame nozzles: there are multiple flame nozzles 12, whose axes are perpendicular to the sample placement area 4, and the multiple flame nozzles form a matrix shape (a 3×5 matrix in this example); each flame nozzle is connected to the inner wall of the box through the same retractable mechanism.
[0044] The retractable mechanism is a metal telescopic sleeve 3; the inner and outer sleeves are secured by screws. For the upper set of flame nozzles, the telescopic sleeves in the retractable mechanism are connected to the side wall of the box via a crossbeam. For the upper set of flame nozzles, the telescopic sleeves in the retractable mechanism are directly connected to the bottom of the box.
[0045] The fuel pipe connected to the flame nozzle air inlet is a fire-resistant hose, and the fuel pipe connected to the fire-resistant hose air inlet is made of metal. The perforated connection between the fuel pipe and the side wall of the box is welded.
[0046] Further references Figure 3 The propane gas source 29 and the air source 30 are connected to the air inlet of the fuel pipeline through the mixed gas valve 27.
[0047] Further references Figure 4 The nitrogen source 31, the carbon dioxide source 32 and the oxygen source 33 are respectively connected to the air inlet of the four-way pipe 28, and the air outlet of the four-way pipe is connected to the gas inlet 17; there are valves (for flow limiting) on the three air inlets of the four-way pipe; the nitrogen source, the carbon dioxide source and the oxygen source are all atmospheric pressure gas sources.
[0048] Further references Figure 5 A transition duct 11 is connected between the air inlet of the smoke concentration detection channel 19 and the pipeline. The air inlet of the transition duct is the same as the air outlet of the pipeline. The air inlet of the transition duct is the same as the air inlet of the smoke concentration detection channel. The inner cavity of the transition duct is truncated cone-shaped. The transition duct gradually reduces the smoke pressure through the transition duct, making the pressure and velocity in the smoke concentration detection channel relatively stable.
Claims
1. A flame retardant performance test box for cable flame retardant materials, comprising a fire-resistant box body, a sample rack, a fire source, a gas inlet, a sensor and an exhaust port installed in the box body, characterized in that The box body is connected to a door that can be opened and closed, and the door has a sealing structure; the side wall of the box body is connected to an observation window; Each wall of the box body is a three-layer structure, which is a ceramic layer, an asbestos layer and a steel plate layer from the inside to the outside. The box body is installed on the bracket, and the bottom of the box body is suspended in the air. The sample rack is located in the center of the cavity in the box body, and has a sample placement area on the sample rack; the structure of the sample rack includes two pairs of clamping blocks, and the sample placement area is between the two pairs of clamping blocks, and the sample placement area is in the shape of a flat plate; the inner wall of each pair of clamping blocks has a ceramic layer; There are multiple fire sources, and the flame nozzles of the fire sources are connected to the combustion gas source through fuel pipes; each flame nozzle faces the sample placement area; each flame nozzle has an independent fuel pipe and ignition device; the air inlet of the fuel pipe is connected to the air outlet of the mixed gas source of combustible gas and oxygen, and the ratio of the two gases in the mixed gas source is adjustable; The gas inlet is located on the bottom surface of the box below the sample placement area, and the gas inlet is connected to a mixed gas source of nitrogen, carbon dioxide and oxygen; the ratio of the three gases in the mixed gas source is adjustable; The exhaust port is located on the top surface of the box above the sample placement area, and a gas collecting hopper is connected above the exhaust port. The gas outlet of the gas collecting hopper is connected to the smoke concentration detection channel through an air pipe, and the gas outlet of the smoke concentration detection channel is connected to the air pipe; the inner cavity of the gas collecting hopper is in the shape of a trumpet with a large air inlet and a small air outlet; the inner cavity of the smoke concentration detection channel is in the shape of a cylinder, and the diameter of the cylinder is larger than the diameter of the air pipes at both ends thereof; a smoke concentration sensor is arranged in the middle position of the smoke concentration detection channel; Install a toxic gas sensor in the gas collecting hopper; A plurality of thermocouples are installed in the box, and each thermocouple is divided into a plurality of groups, and the distance between each group of thermocouples and the sample placement area is the same.
2. The flame retardant performance test box for cable flame retardant materials according to claim 1 is characterized in that The door is located at the center of the top of the box; the exhaust port is located on the door, and the air inlet of the gas collecting hopper is connected to the exhaust port through a sealing structure; the sample rack is connected to the inner side of the door through a connecting rod.
3. The flame retardant performance test box for cable flame retardant materials according to claim 2, characterized in that There are two groups of flame nozzles, which are respectively located at the upper and lower sides of the sample placement area; In each group of flame nozzles: There are multiple flame nozzles, their axes are perpendicular to the sample placement area, and the multiple flame nozzles form a matrix shape; each flame nozzle is connected to the inner wall of the box through the same telescopic mechanism.
4. The flame retardant performance test box for cable flame retardant materials according to claim 3, characterized in that The telescopic mechanism is a telescopic sleeve made of metal; the inner and outer sleeves of the telescopic sleeve are limited by fastening screws.
5. The flame retardant performance test box for cable flame retardant materials according to claim 1, characterized in that The gas source of the combustible gas and the gas source of the air are connected to the gas inlet of the fuel pipeline through a mixed gas valve.
6. The flame retardant performance test box for cable flame retardant materials according to claim 1, characterized in that The nitrogen source, carbon dioxide source and oxygen source are respectively connected to the air inlet of the four-way pipe, and the air outlet of the four-way pipe is connected to the gas inlet; there are valves on the three air inlets of the four-way pipe; the nitrogen source, carbon dioxide source and oxygen source are all atmospheric pressure gas sources.
7. The flame retardant performance test box for cable flame retardant materials according to claim 1, characterized in that A transition pipe is connected between the air inlet of the smoke concentration detection channel and the pipeline. The air inlet of the transition pipe is the same as the air outlet of the pipeline. The air inlet of the transition pipe is the same as the air inlet of the smoke concentration detection channel. The inner cavity of the transition pipe is a truncated cone shape.