Solid spontaneous ignition point testing device and testing method

Abstract

The invention belongs to the technical field of chemical physical risk identification, and particularly discloses a solid spontaneous ignition point testing device and method. The testing device comprises a heating furnace, a sample container and a computer control monitor, the heating furnace comprises a hearth and a hearth cover, the hearth is detachably connected with the hearth cover, and the sample container is suspended in the hearth after being connected with the hearth cover. An oxygen concentration analyzer is arranged in the hearth, and a first thermocouple sensor is arranged on the inner side wall of the hearth. A transparent visible observation window is arranged on the hearth cover opposite to the sample container, and an air disperser, a flame detector, a second thermocouple sensor and a third thermocouple sensor are arranged on the hearth cover; the second thermocouple sensor and the third thermocouple sensor are used for monitoring the temperature of a sample; and the second thermocouple sensor and the third thermocouple sensor extend into different heights in the sample to be tested in the sample container. The method effectively overcomes the defect that an existing solid spontaneous ignition point testing method is too single in judgment criterion, and the solid spontaneous ignition point testing precision and applicability are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of identifying the physical hazards of chemicals, and particularly relates to a device and method for testing the spontaneous ignition point of solids. Background Art

[0002] Spontaneous combustion refers to the phenomenon that a combustible substance spontaneously ignites in the air without an external ignition source, by continuously accumulating heat through its own heat generation or external heating. The spontaneous ignition point, that is, the lowest ambient temperature required for the system to undergo spontaneous combustion, is a parameter characterizing the likelihood or ease of a substance to undergo spontaneous combustion, and is an important indicator for measuring the fire hazard of combustibles. The lower the spontaneous ignition point of a combustible substance, the easier it is to cause spontaneous combustion, and the greater its fire hazard. Due to its suddenness, spontaneous combustion often causes fires in storage, transportation and other links without any warning, posing a great threat to public safety. Therefore, accurately measuring the spontaneous ignition point of combustibles has important guiding significance for the safe storage and transportation of chemicals.

[0003] According to different furnace temperature control methods, the heating test methods used in the laboratory to test the spontaneous ignition point of chemicals can be divided into the constant heating rate method (CHR) and the heat - wait - search method (HWS). In the CHR method, the test sample is heated at a constant rate until the sample undergoes spontaneous combustion, and the ambient temperature at this time is the spontaneous ignition point; in the HWS method, the test sample is added to a test container that has been heated to a set temperature, observed for a period of time until spontaneous combustion occurs, and the set temperature is the spontaneous ignition temperature. If spontaneous combustion does not occur, the set temperature is increased and the above process is repeated. Compared with the HWS method, the CHR method can determine the spontaneous ignition point with only one heating process, has a simple process, a fast test speed, and less sample consumption, and is widely used in the test of the spontaneous ignition point of solids.

[0004] Currently, the standards referred to in the laboratory for testing the spontaneous ignition point of solid chemicals are mainly "GB / T21756 - 2008 Determination of the relative spontaneous ignition temperature of solid substances of chemical products for industrial use" and "EC440 - 2008 A.16 Relative spontaneous ignition temperature of solids", both using the CHR method, but having the following disadvantages: (1) Only determining the spontaneous ignition temperature of the sample based on the heating chamber temperature corresponding to when the sample temperature reaches 400°C, the judgment criterion is too single, and problems such as the thermocouple deviating from the center of the sample and insufficient oxygen supply during the test process may lead to low accuracy and poor reliability of the test results; (2) The sample container is a metal wire basket, which is difficult to meet the test requirements for the spontaneous ignition point of low - melting - point solid products. Summary of the Invention

[0005] An object of the present invention is to provide a device for testing the spontaneous ignition point of solids, effectively solving the problems of a single judgment criterion in the prior art and low accuracy of test results caused by the thermocouple deviating from the center of the sample and insufficient oxygen supply during the test process.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A solid spontaneous ignition point test device, comprising a heating furnace, a specimen container and a computer control monitor. The heating furnace includes a furnace chamber and a furnace cover located at the top of the furnace chamber. The furnace chamber and the furnace cover are detachably connected. The specimen container is connected to the furnace cover by a metal wire and suspended in the furnace chamber.

[0008] An oxygen concentration analyzer is provided in the furnace chamber. A first thermocouple sensor is provided on the inner side wall of the furnace chamber. Both the oxygen concentration analyzer and the first thermocouple sensor are connected to the computer control monitor.

[0009] A transparent and visible observation window is provided at a position on the furnace cover opposite to the specimen container. An air disperser, a flame detector, a second thermocouple sensor and a third thermocouple sensor for monitoring the temperature of the specimen are provided on the furnace cover. The second thermocouple sensor and the third thermocouple sensor extend into the specimen to be tested in the specimen container at different heights and are connected to the computer control monitor. The air disperser and the flame detector both extend into the furnace chamber and are connected to the computer control monitor.

[0010] Further, the specimen container has a double-layer structure of an upper basket and a lower tray. The bottom area of the sample tray located directly below is larger than the bottom area of the sample basket located directly above.

[0011] Further, a nitrogen nozzle for injecting nitrogen into the furnace chamber is provided on the inner side wall of the furnace chamber. The nitrogen nozzle is connected to the nitrogen output pipeline of a nitrogen generator. An electromagnetic valve for controlling the on-off of the pipeline is provided on the nitrogen output pipeline. The electromagnetic valve is connected to the computer control monitor.

[0012] Further, a lifting slide rod for driving the opening and closing of the furnace cover is provided on the heating furnace. A reflecting mirror for observing the situation inside the furnace chamber is provided on the lifting slide rod.

[0013] Further, the observation window is made of high-temperature glass.

[0014] Further, the sample basket is a cube without an upper surface folded from a stainless steel wire mesh, and the sample tray is made of a stainless steel plate.

[0015] Further, the second thermocouple sensor is inserted into the central position of the specimen, and the third thermocouple sensor is inserted into the specimen 5 mm further downward than the bottom end of the second thermocouple sensor.

[0016] Further, a radiator is also provided on the furnace chamber. The radiator is connected to the computer control monitor.

[0017] Further, the air disperser is made of copper pipe. The copper pipe first extends downward into the furnace and turns to one side when approaching the inner bottom wall of the furnace, and then approaches one side wall in a coiled or wave-shaped manner. When approaching one side wall, it turns upward and extends above the sample container, and finally turns to extend to the opposite side wall. The tail end of the copper pipe is provided with a plurality of downward-extending branches parallel to each other, and a part of the branches are located in the sample basket and the other part of the branches are located in the furnace.

[0018] Further, there are a plurality of nitrogen nozzles, and the plurality of nitrogen nozzles are arranged in pairs opposite to each other; there are a plurality of first thermocouple sensors, and the plurality of first thermocouple sensors are arranged in pairs opposite to each other.

[0019] Another object of the present invention is to provide a method for testing the spontaneous ignition point of solids, effectively solving the problems of single determination criterion in the prior art and low accuracy of test results caused by the thermocouple deviating from the center of the sample, insufficient oxygen supply during the test process, etc.

[0020] To solve the above technical problems, the technical solution adopted by the present invention is:

[0021] A method for testing the spontaneous ignition point of solids, using the solid spontaneous ignition point testing device as described in the above embodiment, includes the following steps:

[0022] S1. Lift the furnace cover, load the sample into the sample basket, gently tap and compact it, and then add more samples until the sample basket is completely filled.

[0023] S2. Insert the second thermocouple sensor into the center position of the sample, and insert the third thermocouple sensor into the sample at a position 5 mm lower than the bottom end of the second thermocouple sensor.

[0024] S3. After covering the furnace with the furnace cover, turn on the heating furnace. Enter the test interface on the computer control monitor, set the sample information, air flow rate, target temperature and heating rate, and then start the test.

[0025] S4. During the test process, observe the actual state of the sample in real time. When the center temperature of the sample detected by the second thermocouple sensor and the third thermocouple sensor reaches the target temperature, or the flame detector recognizes that the sample has flaming combustion, or the temperature detected by the second thermocouple sensor and the third thermocouple sensor exceeds the temperature detected by the first thermocouple sensor by 80 °C, the test ends. The heating furnace stops heating and stops injecting air. At this time, the temperature detected by the first thermocouple sensor is the spontaneous ignition point of the sample.

[0026] When the flame detector detects a flaming combustion of the sample, it transmits a signal to the computer control monitor, the solenoid valve opens, and nitrogen is filled into the furnace through the nitrogen nozzle until the alarm signal of the flame detector disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace drops to a certain level, then the solenoid valve closes and the nitrogen filling stops.

[0027] S5. Raise the furnace cover to separate the sample container from the furnace.

[0028] Further, the target temperature is 400 °C; when the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace drops below 5%, the solenoid valve closes.

[0029] The beneficial technical effects of the present invention are:

[0030] (1) By designing the sample container as a double-layer structure with an upper basket and a lower tray, the present invention not only ensures that as much oxygen as possible in the furnace smoothly enters the sample, but also avoids the leakage of melted low-melting-point solids, filling the blank in the test of the autoignition point of low-melting-point solids.

[0031] (2) By setting up a flame detector, the present invention can automatically and effectively identify flaming combustion and use it as an auxiliary means to determine the autoignition point of the sample.

[0032] (3) By setting up a nitrogen nozzle, the present invention jointly forms a heat dissipation and fire extinguishing device with the flame detector, the nitrogen nozzle and the oxygen concentration analyzer. When the flame detector detects a flaming combustion of the sample, it transmits a signal to the computer control monitor, the solenoid valve opens, and nitrogen is filled into the furnace through the nitrogen nozzle until the alarm signal of the flame detector disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace drops below 5%, then the solenoid valve closes and the nitrogen filling stops, improving the safety and working efficiency of the test process.

[0033] (4) By designing a reflecting mirror and a high-temperature observation window glass, the present invention facilitates the real-time observation of the actual state of the sample during the test.

[0034] (5) By designing a double thermocouple sensor for monitoring the sample temperature, the present invention avoids the problem that the thermocouple sensor cannot detect the true temperature inside the sample due to the shrinkage and detachment of the low-density sample from the thermocouple sensor after heating, thus interfering with the autoignition point test result.

[0035] (6) By adding an air disperser, the present invention disperses air into the sample to be tested and the heating furnace at a stable and controllable appropriate flow rate, avoiding the problem of insufficient oxygen supply during the oxidation process of the sample.

[0036] (7) By comparing and analyzing relevant domestic and foreign standards such as EN 15188-2007 and VDI 2263, and combining with the analysis of test results, the present invention proposes that any of the following states can be determined as reaching the autoignition point: (a) the phenomenon of flaming combustion is observed; (b) the central temperature of the sample reaches 400 °C; (c) the temperature record shows that the central temperature of the sample exceeds the temperature of the heating furnace by at least 80 °C. A multi-criterion device and method for determining the autoignition point of solids are provided, effectively overcoming the disadvantages of the existing test methods for the autoignition point of solids, such as overly single determination criteria, low accuracy and poor reliability of test results that may be caused by problems such as the thermocouple deviating from the center of the sample and insufficient oxygen supply during the test process, filling the blank of the test for the autoignition point of low-melting-point solids, and improving the test accuracy and applicability of the autoignition point of solids. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are those of some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a schematic structural diagram of the device for testing the autoignition point of solids of the present invention.

[0039] In the figure: 1 - furnace chamber; 2 - furnace chamber cover; 3 - observation window; 4 - sample container; 5 - air disperser; 6 - second thermocouple sensor;

[0040] 7 - third thermocouple sensor; 8 - mirror; 9 - flame detector; 10 - nitrogen nozzle; 11 - computer control monitor;

[0041] 12 - first thermocouple sensor; 13 - lifting slide bar. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] Embodiment 1

[0043] As Figure 1 shown, a device for testing the autoignition point of solids includes a heating furnace, a sample container 4 and a computer control monitor 11. The heating furnace includes a furnace chamber 1 and a furnace chamber cover 2 located at the top of the furnace chamber. The furnace chamber 1 and the furnace chamber cover 2 are detachably connected. The sample container 4 is connected to the furnace chamber cover 2 by a metal wire and suspended in the furnace chamber 1.

[0044] An oxygen concentration analyzer is provided in the furnace chamber 1, and a first thermocouple sensor 12 is provided on the inner side wall of the furnace chamber 1. Both the oxygen concentration analyzer and the first thermocouple sensor 12 are connected to the computer control monitor 11.

[0045] A transparent and visible observation window 3 is provided at a position on the furnace lid 2 opposite to the sample container 4, and the observation window 3 is made of high-temperature glass.

[0046] An air disperser 5, a flame detector 9, a second thermocouple sensor 6 and a third thermocouple sensor 7 for monitoring the sample temperature are provided on the furnace lid 2. The second thermocouple sensor 6 and the third thermocouple sensor 7 extend into the sample to be tested in the sample container 4 at different heights and are connected to a computer control monitor 11. The air disperser is externally connected to an air source, and both the air disperser 5 and the flame detector 9 extend into the furnace 1 and are connected to the computer control monitor 11.

[0047] In some specific embodiments, the second thermocouple sensor 6 is inserted into the center position of the sample, and the third thermocouple sensor 7 is inserted into the sample 5 mm further downward than the bottom end of the second thermocouple sensor 6.

[0048] In some specific embodiments, the air disperser 5 disperses the air heated in the furnace into the sample container 4 and the furnace 1 in a coiled pipe manner and at a flow rate of 50 mL / min. To avoid the problem of insufficient oxygen supply during the oxidation of the sample. Specifically, the air disperser 5 is made of a copper pipe. The copper pipe first extends downward into the furnace 1 until it is close to the inner bottom wall of the furnace 1 and then turns to one side and approaches the right side wall in a coiled pipe or wave shape. When it is close to the right side wall, it turns upward and extends above the sample container 4, and finally turns to the left side wall and extends. Five parallel downward-extending branches are provided at the tail end of the copper pipe, three of which are located in the sample container 4 and two are located in the furnace 1.

[0049] By setting the flame detector 9 in the present invention, it is possible to automatically and effectively identify flaming combustion and determine the autoignition point of the sample as an auxiliary means.

[0050] By designing a double thermocouple sensor for monitoring the sample temperature, it is possible to avoid the problem that the sample with a small density shrinks and detaches from the thermocouple sensor after being heated, resulting in the thermocouple sensor being unable to detect the true temperature inside the sample and thus interfering with the test result of the autoignition point.

[0051] By adding an air disperser 5, the air is dispersed into the sample to be tested and the heating furnace 1 at a stable and controllable appropriate flow rate, avoiding the problem of insufficient oxygen supply during the oxidation of the sample.

[0052] A method for testing the autoignition point of a solid using the solid autoignition point testing device described in this embodiment includes the following steps:

[0053] S1. Raise the furnace lid 2, load the sample into the sample container 4, gently tap and compact it, and then add more samples until the sample container 4 is completely filled.

[0054] S2. Insert the second thermocouple sensor 6 into the center position of the specimen, and insert the third thermocouple sensor 7 into the specimen at a position 5 mm further down than the bottom end of the second thermocouple sensor 6.

[0055] S3. After covering the furnace with the furnace lid 2, turn on the heating furnace. Enter the test interface on the computer control monitor, set the specimen information, air flow rate, target temperature of 400 °C, and heating rate, and then start the test.

[0056] S4. During the test, observe the actual state of the sample in real time. When the center temperature of the specimen detected by the second thermocouple sensor 6 and the third thermocouple sensor 7 reaches the target temperature of 400 °C, or the flame detector recognizes that the specimen has a flaming combustion, or the temperature detected by the second thermocouple sensor 6 and the third thermocouple sensor 7 exceeds the temperature detected by the first thermocouple sensor 12 by 80 °C, the test ends. The heating furnace stops heating and the air injection stops. At this time, the temperature detected by the first thermocouple sensor 12 is the autoignition temperature of the specimen.

[0057] S5. Raise the furnace lid 2 to separate the specimen container 4 from the furnace chamber 1.

[0058] By comparing and analyzing relevant domestic and foreign standards such as EN 15188-2007 and VDI 2263, and combining with the analysis of the test results, the present invention obtains that when any of the following states occurs, it can be determined that the autoignition point has been reached: (a) observing a flaming combustion phenomenon; (b) the center temperature of the sample reaches 400 °C; (c) the temperature record shows that the center temperature of the sample exceeds the temperature of the heating furnace by at least 80 °C.

[0059] Compared with the prior art, the present invention provides a multi-criterion method for determining the autoignition point of solids. The present invention effectively overcomes the disadvantages of the existing method for testing the autoignition point of solids, where the determination criteria are too single, and may lead to low accuracy and poor reliability of the test results due to problems such as the thermocouple being separated from the center of the sample and insufficient oxygen supply during the test process, and improves the test accuracy of the autoignition point of solids.

[0060] Embodiment 2

[0061] As Figure 1 shown, a test device for the autoignition point of solids includes a heating furnace, a specimen container 4, and a computer control monitor 11. The heating furnace includes a furnace chamber 1 and a furnace lid 2 located at the top of the furnace chamber. The furnace chamber 1 and the furnace lid 2 are detachably connected. The specimen container 4 is connected to the furnace lid 2 by a metal wire and suspended in the furnace chamber 1.

[0062] An oxygen concentration analyzer is provided in the furnace chamber 1, and a first thermocouple sensor 12 is provided on the inner side wall of the furnace chamber 1. Both the oxygen concentration analyzer and the first thermocouple sensor 12 are connected to the computer control monitor 11.

[0063] In some embodiments, there are multiple first thermocouple sensors 12, and the multiple first thermocouple sensors 12 are arranged in pairs opposite to each other.

[0064] A transparent and visible observation window 3 is provided at a position on the furnace cover 2 opposite to the sample container 4, and the observation window 3 is made of high-temperature glass.

[0065] An air disperser 5, a flame detector 9, a second thermocouple sensor 6 and a third thermocouple sensor 7 for monitoring the sample temperature are provided on the furnace cover 2. The second thermocouple sensor 6 and the third thermocouple sensor 7 extend into the sample to be tested in the sample container 4 at different heights and are connected to the computer control monitor 11. The air disperser 5 is externally connected to an air source, and both the air disperser 5 and the flame detector 9 extend into the furnace 1 and are connected to the computer control monitor 11.

[0066] In some specific embodiments, a nitrogen nozzle 10 for injecting nitrogen into the furnace 1 is further provided on the inner side wall of the furnace 1. The nitrogen nozzle 10 is connected to the nitrogen output pipeline of the nitrogen generator, and an electromagnetic valve for controlling the on / off of the pipeline is provided on the nitrogen output pipeline. The electromagnetic valve is connected to the computer control monitor 11.

[0067] In some embodiments, there are multiple nitrogen nozzles 10, and the multiple nitrogen nozzles 10 are arranged in pairs opposite to each other.

[0068] In some specific embodiments, the second thermocouple sensor 6 is inserted into the central position of the sample, and the third thermocouple sensor 7 is inserted 5 mm further downward than the bottom end of the second thermocouple sensor 6 in the sample.

[0069] In some specific embodiments, the air disperser 5 uses a copper pipe to disperse the air heated in the furnace into the sample container 4 and the furnace 1 in the form of a coil at a flow rate of 50 mL / min, avoiding the problem of insufficient oxygen supply during the oxidation process of the sample.

[0070] By providing the flame detector 9, the present invention can automatically and effectively identify flaming combustion and determine the autoignition point of the sample as an auxiliary means.

[0071] By providing the nitrogen nozzle 10, a heat dissipation and fire extinguishing device is jointly composed of the flame detector 9, the nitrogen nozzle 10 and the oxygen concentration analyzer. When the flame detector 9 identifies that the sample has flaming combustion, it transmits a signal to the computer control monitor 11, the electromagnetic valve opens, and nitrogen is filled into the furnace 1 through the nitrogen nozzle 10 until the alarm signal of the flame detector 9 disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace drops below 5%, then the electromagnetic valve closes and stops filling nitrogen, improving the safety and working efficiency of the test process.

[0072] By designing a double thermocouple sensor to monitor the sample temperature, it is possible to avoid the problem that a small-density sample shrinks and detaches from the thermocouple sensor after being heated, resulting in the thermocouple sensor being unable to detect the true temperature inside the sample and thus interfering with the test results of the spontaneous ignition point.

[0073] By adding an air disperser 5, air is dispersed into the sample to be tested and the heating furnace 1 at a stable and controllable appropriate flow rate, avoiding the problem of insufficient oxygen supply during the oxidation process of the sample.

[0074] A method for testing the spontaneous ignition point of a solid using the solid spontaneous ignition point testing device described in this embodiment includes the following steps:

[0075] S1. Raise the furnace lid 2, load the sample into the sample container 4, gently tap and compact it, and then add more samples until the sample container 4 is completely filled.

[0076] S2. Insert the second thermocouple sensor 6 into the center position of the sample, and insert the third thermocouple sensor 7 into the sample at a position 5 mm below the bottom end of the second thermocouple sensor 6.

[0077] S3. After covering the furnace 1 with the furnace lid 2, turn on the heating furnace. Enter the test interface on the computer control monitor 11, set the sample information, air flow rate, target temperature of 400 °C, and heating rate, and then start the test.

[0078] S4. During the test, observe the actual state of the sample in real time. When the second thermocouple sensor 6 and the third thermocouple sensor 7 detect that the center temperature of the sample reaches the target temperature of 400 °C, or the flame detector recognizes that the sample has a flaming combustion, or the temperature detected by the second thermocouple sensor 6 and the third thermocouple sensor 7 exceeds the temperature detected by the first thermocouple sensor 12 by 80 °C, the test ends. The heating furnace stops heating and the air injection stops. At this time, the temperature detected by the first thermocouple sensor 12 is the spontaneous ignition point of the sample.

[0079] When the flame detector 9 recognizes that the sample has a flaming combustion, it transmits a signal to the computer control monitor 11, the solenoid valve opens, and nitrogen is filled into the furnace 1 through the nitrogen nozzle 10 until the alarm signal of the flame detector 9 disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace drops to a certain level, then the solenoid valve closes and the nitrogen filling stops.

[0080] S5. Raise the furnace lid 2 to separate the sample container 4 from the furnace 1.

[0081] Through comparative analysis of relevant domestic and foreign standards such as EN 15188-2007 and VDI 2263, and combined with the analysis of test results, it is determined that the auto-ignition point is reached when any of the following states occur: (a) Flame combustion is observed; (b) The center temperature of the sample reaches 400 °C; (c) The temperature record shows that the center temperature of the sample exceeds the temperature of the heating furnace by at least 80 °C.

[0082] Compared with the prior art, the present invention provides a multi-criterion method for determining the auto-ignition point of solids. The present invention effectively overcomes the disadvantages of the existing method for testing the auto-ignition point of solids, such as too single determination criteria, and may lead to low accuracy and poor reliability of the test results due to problems such as the thermocouple being separated from the center of the sample and insufficient oxygen supply during the test process, and improves the test accuracy of the auto-ignition point of solids.

[0083] Embodiment 3

[0084] As Figure 1 shown, a test device for the auto-ignition point of solids includes a heating furnace, a specimen container 4 and a computer control monitor 11. The heating furnace includes a furnace chamber 1 and a furnace lid 2 located at the top of the furnace chamber. The furnace chamber 1 and the furnace lid 2 are detachably connected. The specimen container 4 is connected to the furnace lid 2 by a metal wire and suspended in the furnace chamber 1.

[0085] In this embodiment, the specimen container 4 has a double-layer structure of an upper basket and a lower tray. The bottom area of the sample tray located directly below is larger than the bottom area of the sample basket located directly above. This structural design not only avoids the floating and slipping of small-density specimens or the melting and leakage of low-melting-point samples, but also ensures that as much oxygen as possible in the furnace chamber smoothly enters the interior of the specimen.

[0086] In some embodiments, the sample basket is a cube without an upper surface folded from a stainless steel wire mesh with a mesh diameter of 45 μm, and the sample tray is made of a stainless steel plate with a thickness of 0.5 mm. The side length of the sample basket is 20 mm; the diameter of the sample tray is 30 mm and the depth is 10 mm. The sample tray and the sample basket are connected together.

[0087] An oxygen concentration analyzer is provided in the furnace chamber 1, and a first thermocouple sensor 12 is provided on the inner side wall of the furnace chamber 1. The oxygen concentration analyzer and the first thermocouple sensor 12 are both connected to the computer control monitor 11.

[0088] In some embodiments, there are multiple first thermocouple sensors 12, and the multiple first thermocouple sensors 12 are arranged opposite to each other in pairs.

[0089] A transparent and visible observation window 3 is provided at the position of the furnace lid 2 opposite to the specimen container 4. The observation window 3 is made of high-temperature glass.

[0090] An air distributor 5, a flame detector 9, a second thermocouple sensor 6 and a third thermocouple sensor 7 for monitoring the temperature of the specimen are provided on the furnace lid 2. The second thermocouple sensor 6 and the third thermocouple sensor 7 extend into the specimen to be tested in the specimen container 4 at different heights and are connected to a computer control monitor 11. The air distributor 5 is externally connected to an air source. Both the air distributor 5 and the flame detector 9 extend into the furnace 1 and are connected to the computer control monitor 11.

[0091] In some specific embodiments, a nitrogen nozzle 10 for injecting nitrogen into the furnace 1 is further provided on the inner side wall of the furnace 1. The nitrogen nozzle 10 is connected to the nitrogen output pipeline of a nitrogen generator. An electromagnetic valve for controlling the on / off of the pipeline is provided on the nitrogen output pipeline, and the electromagnetic valve is connected to the computer control monitor 11.

[0092] In some embodiments, there are multiple nitrogen nozzles 10, and the multiple nitrogen nozzles 10 are arranged opposite to each other in pairs.

[0093] In some specific embodiments, the second thermocouple sensor 6 is inserted into the central position of the specimen, and the third thermocouple sensor 7 is inserted into the specimen 5 mm further downward than the bottom end of the second thermocouple sensor 6.

[0094] In some specific embodiments, the air distributor 5 uses a copper pipe to disperse the air heated in the furnace into the specimen container 4 and the furnace 1 in the form of a coil at a flow rate of 50 mL / min, avoiding the problem of insufficient oxygen supply during the oxidation process of the sample.

[0095] By designing the specimen container 4 as a double-layer structure with an upper basket and a lower tray, the present invention not only ensures that as much oxygen as possible in the furnace smoothly enters the interior of the specimen, but also avoids the leakage of melted low-melting-point solids, filling the blank in the test of the spontaneous ignition point of low-melting-point solids.

[0096] By providing the flame detector 9, it can automatically and effectively identify flaming combustion and determine the spontaneous ignition point of the specimen as an auxiliary means.

[0097] By providing the nitrogen nozzle 10, a heat dissipation and fire extinguishing device is jointly composed of the flame detector 9, the nitrogen nozzle 10 and an oxygen concentration analyzer. When the flame detector 9 identifies that the specimen has flaming combustion, it transmits a signal to the computer control monitor 11, the electromagnetic valve opens, and nitrogen is filled into the furnace 1 through the nitrogen nozzle 10 until the alarm signal of the flame detector 9 disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace 1 drops below 5%, then the electromagnetic valve closes and stops filling nitrogen, improving the safety and working efficiency of the test process.

[0098] By designing a double thermocouple sensor to monitor the sample temperature, it is possible to avoid the problem that a small-density specimen shrinks and detaches from the thermocouple sensor after being heated, resulting in the thermocouple sensor being unable to detect the true temperature inside the specimen and thus interfering with the autoignition point test results.

[0099] By adding an air disperser 5, air is dispersed into the specimen to be tested and the heating furnace 1 at a stable and controllable appropriate flow rate, avoiding the problem of insufficient oxygen supply during the oxidation process of the specimen.

[0100] A method for testing the autoignition point of a solid using the solid autoignition point testing device described in this embodiment includes the following steps:

[0101] S1. Raise the furnace lid 2, load the specimen into the sample basket, gently tap and compact it, and then add more samples until the sample basket is completely filled.

[0102] S2. Insert the second thermocouple sensor 6 into the center position of the specimen, and insert the third thermocouple sensor 7 into the specimen at a position 5 mm below the bottom end of the second thermocouple sensor 6.

[0103] S3. After closing the furnace with the furnace lid 2, turn on the heating furnace. Enter the test interface on the computer control monitor 11, set the specimen information, air flow rate, target temperature of 400 °C, and heating rate, and then start the test.

[0104] S4. During the test, observe the actual state of the sample in real time. When the second thermocouple sensor 6 and the third thermocouple sensor 7 detect that the center temperature of the specimen reaches the target temperature of 400 °C, or the flame detector recognizes that the specimen has a flaming combustion, or the temperature detected by the second thermocouple sensor 6 and the third thermocouple sensor 7 exceeds the temperature detected by the first thermocouple sensor 12 by 80 °C, the test ends. The heating furnace stops heating and the air injection stops. At this time, the temperature detected by the first thermocouple sensor 12 is the autoignition point of the specimen.

[0105] When the flame detector 9 recognizes that the specimen has a flaming combustion, it transmits a signal to the computer control monitor 11, the solenoid valve opens, and nitrogen is filled into the furnace 1 through the nitrogen nozzle 10 until the alarm signal of the flame detector 9 disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace 1 has dropped to a certain level, then the solenoid valve closes and the nitrogen filling stops.

[0106] S5. Raise the furnace lid 2 to separate the specimen container from the furnace.

[0107] The present invention obtains that when any of the following states occurs, it can be determined that the autoignition point has been reached by comparative analysis of relevant domestic and foreign standards such as EN 15188-2007 and VDI 2263 and combined with the analysis of test results: (a) the phenomenon of flaming combustion is observed; (b) the central temperature of the sample reaches 400 °C; (c) the temperature record shows that the central temperature of the sample exceeds the temperature of the heating furnace by at least 80 °C.

[0108] Compared with the prior art, the present invention provides a multi-criterion method for determining the autoignition point of solids. The present invention effectively overcomes the disadvantages of the prior art that the determination criteria of the existing solid autoignition point test method are too single, and may lead to low accuracy and poor reliability of the test results due to problems such as the thermocouple detaching from the center of the sample and insufficient oxygen supply during the test process, and fills the blank of the low-melting-point solid autoignition point test, improving the test accuracy and applicability of the solid autoignition point.

[0109] Embodiment 4

[0110] As Figure 1 shown, a solid autoignition point test device includes a heating furnace, a specimen container 4 and a computer control monitor 11. The heating furnace includes a furnace chamber 1 and a furnace cover 2 located at the top of the furnace chamber. The furnace chamber 1 and the furnace cover 2 are detachably connected. The specimen container 4 is connected to the furnace cover 2 by a metal wire and suspended in the furnace chamber 1.

[0111] In this embodiment, a radiator is provided on the furnace chamber 1, and the radiator is connected to the computer control monitor 11.

[0112] In some specific embodiments, the specimen container 4 has a double-layer structure of an upper basket and a lower tray, and the bottom area of the sample tray located directly below is larger than the bottom area of the sample basket located directly above. This structural design not only avoids the floating and slipping of small-density specimens or the melting and leakage of low-melting-point samples, but also ensures that as much oxygen as possible in the furnace chamber 1 smoothly enters the interior of the specimen.

[0113] In some embodiments, the sample basket is a cube without an upper surface folded from a stainless steel wire mesh with a mesh diameter of 45 μm, and the sample tray is made of a stainless steel plate with a thickness of 0.5 mm. The side length of the sample basket is 20 mm; the diameter of the sample tray is 30 mm and the depth is 10 mm. The sample tray and the sample basket are connected together.

[0114] An oxygen concentration analyzer is provided in the furnace chamber 1, and a first thermocouple sensor 12 is provided on the inner side wall of the furnace chamber 1. Both the oxygen concentration analyzer and the first thermocouple sensor 12 are connected to the computer control monitor 11.

[0115] In some embodiments, there are multiple first thermocouple sensors 12, and the multiple first thermocouple sensors 12 are arranged opposite to each other in pairs.

[0116] A transparent and visible observation window 3 is provided at a position on the furnace lid 2 opposite to the sample container 4, and the observation window 3 is made of high-temperature glass.

[0117] In this embodiment, a lifting slide rod 13 for driving the opening and closing of the furnace lid 2 is provided on the heating furnace, positioning protrusions are provided on both side walls of the top of the furnace chamber 1, and positioning recesses are provided at positions corresponding to the positioning protrusions on the furnace lid. The positioning protrusions and the positioning recesses are connected in a concave-convex fit. When the furnace lid 2 is closed by the lifting slide rod 13, the furnace lid 2 stops descending when it reaches the positioning protrusions.

[0118] A reflecting mirror 8 for observing the situation inside the furnace chamber 1 is provided on the lifting slide rod 13. By designing the reflecting mirror 8 and the high observation window 3, it is convenient to observe the actual state of the sample in real time during the test.

[0119] An air disperser 5, a flame detector 9, a second thermocouple sensor 6 and a third thermocouple sensor 7 for monitoring the temperature of the sample are provided on the furnace lid 2. The second thermocouple sensor 6 and the third thermocouple sensor 7 extend into the sample to be tested in the sample container 4 at different heights and are connected to a computer control monitor 11. The air disperser 5 is externally connected to an air source. The air disperser 5 and the flame detector 9 both extend into the furnace chamber 1 and are connected to the computer control monitor 11.

[0120] In some specific embodiments, a nitrogen nozzle 10 for injecting nitrogen into the furnace chamber 1 is further provided on the inner side wall of the furnace chamber 1. The nitrogen nozzle 10 is connected to the nitrogen output pipeline of a nitrogen generator. An electromagnetic valve for controlling the on-off of the pipeline is provided on the nitrogen output pipeline, and the electromagnetic valve is connected to the computer control monitor 11.

[0121] In some embodiments, there are multiple nitrogen nozzles 10, and the multiple nitrogen nozzles 10 are arranged in pairs opposite to each other.

[0122] In some specific embodiments, the second thermocouple sensor 6 is inserted into the central position of the sample in the sample container 4, and the third thermocouple sensor 7 is inserted into the sample in the sample container 4 at a position 5 mm further downward than the bottom end of the second thermocouple sensor 6.

[0123] In some specific embodiments, the air disperser 5 uses a copper pipe to disperse the air heated in the furnace chamber 1 into the sample container 4 and the furnace chamber 1 in a coiled tube manner at a flow rate of 50 mL / min. This avoids the problem of insufficient oxygen supply during the oxidation process of the sample.

[0124] By designing the sample container 4 as a double-layer structure with an upper basket and a lower tray, it not only ensures that as much oxygen as possible in the furnace 1 smoothly enters the interior of the sample, but also avoids the leakage of molten low-melting solids, filling the gap in the test of the spontaneous ignition point of low-melting solids.

[0125] By setting up the flame detector 9, it can automatically and effectively identify flaming combustion, and be used as an auxiliary means to determine the spontaneous ignition point of the sample.

[0126] By setting up the nitrogen nozzle 10, a heat dissipation and fire extinguishing device is jointly composed of the flame detector 9, the nitrogen nozzle 10 and the oxygen concentration analyzer. When the flame detector 9 detects that the sample has flaming combustion, it transmits a signal to the computer control monitor 11, the solenoid valve opens, and nitrogen is filled into the furnace 1 through the nitrogen nozzle 10 until the alarm signal of the flame detector 9 disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace drops below 5%, then the solenoid valve closes and stops filling nitrogen, improving the safety and working efficiency of the test process.

[0127] By designing the reflector 8 and the observation window 3, it is convenient to observe the actual state of the sample in real time during the test.

[0128] By designing a double thermocouple sensor to monitor the sample temperature, it avoids the problem that the sample with a small density shrinks and detaches from the thermocouple sensor after being heated, resulting in the thermocouple sensor being unable to detect the true temperature inside the sample, thus interfering with the test results of the spontaneous ignition point.

[0129] By adding an air disperser 5, the air is dispersed into the sample to be tested and the heating furnace 1 at a stable and controllable appropriate flow rate, avoiding the problem of insufficient oxygen supply during the oxidation process of the sample.

[0130] A method for testing the spontaneous ignition point of a solid using the solid spontaneous ignition point testing device described in this embodiment includes the following steps:

[0131] S1. Raise the furnace cover 2 through the lifting slide rod 13, load the sample into the sample basket, gently tap and compact it, and then add more samples until the sample basket is completely filled.

[0132] S2. Insert the second thermocouple sensor 6 into the center position of the sample, and insert the third thermocouple sensor 7 into the sample at a position 5 mm lower than the bottom end of the second thermocouple sensor 6.

[0133] S3. After covering the furnace with the furnace cover 2, turn on the heating furnace. Enter the test interface on the computer control monitor 11, set the sample information, air flow rate, target temperature of 400 °C and heating rate, and then start the test.

[0134] S4. During the test, observe the actual state of the sample in real time. When the second thermocouple sensor 6 and the third thermocouple sensor 7 detect that the central temperature of the specimen reaches the target temperature of 400 °C, or the flame detector 9 identifies that the specimen has a flaming combustion, or the temperature detected by the second thermocouple sensor 6 and the third thermocouple sensor 7 exceeds the temperature detected by the first thermocouple sensor 12 by 80 °C, the test ends, the heating furnace stops heating, and the air injection stops. At this time, the temperature detected by the first thermocouple sensor 12 is the autoignition temperature of the specimen.

[0135] When the flame detector 9 identifies that the specimen has a flaming combustion, it transmits a signal to the computer control monitor 11, the solenoid valve opens, and nitrogen is filled into the furnace 1 through the nitrogen nozzle 10 until the alarm signal of the flame detector 9 disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace 1 drops to a certain level, then the solenoid valve closes and the nitrogen filling stops.

[0136] S5. Raise the furnace cover 2 through the lifting slide rod 13 to separate the specimen container 4 from the furnace 1.

[0137] By comparing and analyzing relevant domestic and foreign standards such as EN 15188-2007 and VDI 2263, and combining the analysis of the test results, the present invention obtains that when any of the following states occurs, it can be determined that the autoignition point is reached: (a) observing a flaming combustion phenomenon; (b) the central temperature of the sample reaches 400 °C; (c) the temperature record shows that the central temperature of the sample exceeds the temperature of the heating furnace by at least 80 °C.

[0138] Compared with the prior art, the present invention provides a multi-criterion method for determining the autoignition point of solids. The present invention effectively overcomes the disadvantages of the prior art in which the determination criteria of the solid autoignition point test method are too single, and may lead to low test result accuracy and poor reliability due to problems such as the thermocouple being separated from the center of the sample and insufficient oxygen supply during the test process. It also fills the blank of the low-melting-point solid autoignition point test, and improves the test accuracy and applicability of the solid autoignition point.

[0139] Next, the specific embodiments of the present invention will be described in detail in combination with specific examples and comparative examples.

[0140] Example 1

[0141] Use the solid autoignition point test device described in Embodiment 4 to test the autoignition point of pulverized coal, including the following steps:

[0142] First, raise the furnace cover 2 through the lifting slide rod 13, fill the sample basket with the specimen pulverized coal, gently tap and compact it, and then add more samples until the sample basket is completely filled.

[0143] Then insert the second thermocouple sensor 6 into the center position of the specimen, and insert the third thermocouple sensor 7 into the specimen at a position 5 mm lower than the bottom end of the second thermocouple sensor 6.

[0144] After lowering the furnace lid 2 to its original position, turn on the power switch of the heating furnace. Enter the test interface on the computer control monitor 11, set test parameters such as sample information, air flow rate (50 mL / min), target temperature (400 °C), heating rate (0.5 °C / min), etc., and then start the test.

[0145] During the test process, the actual state of the sample can be observed in real time through the mirror 8. When the central temperature of the sample reaches 400 °C, the test ends. The computer control monitor 11 controls the heating furnace to stop heating, stops injecting air, raises the furnace lid 2 to separate the specimen container from the furnace chamber 1, and turns on the radiator blower to cool down.

[0146] The record of the oxygen concentration analyzer shows that the oxygen concentration in the furnace chamber 1 has been stable at about 20%. The test results show that the heating furnace temperature corresponding to when the sample temperature reaches 400 °C is 154.6 °C. It shows that the spontaneous ignition point of the pulverized coal measured in this embodiment is 154.6 °C. Set the control experiment of this embodiment, and use the existing device for testing the spontaneous ignition point of solids to test the spontaneous ignition point of the same pulverized coal. The test result is 155.3 °C, indicating that the method and device for testing the spontaneous ignition point of solids provided by the present invention are stable and reliable during operation and can meet the test requirements.

[0147] Comparative Example 1

[0148] Using the same sample - pulverized coal, test method and test device as in Example 1, the only difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, the air disperser 5 is closed during the test process, and no air is injected into the specimen container 4 and the heating furnace chamber 1.

[0149] The record of the oxygen concentration analyzer shows that the oxygen concentration in the furnace chamber 1 gradually decreases to less than 10%. The test results show that the heating furnace chamber 1 temperature corresponding to when the sample temperature reaches 400 °C in this embodiment is 162.9 °C, indicating that the present invention can effectively avoid the problem of insufficient oxygen supply during the test of the spontaneous ignition point of the sample and improve the accuracy and reliability of the test results.

[0150] Example 2

[0151] Use the device for testing the spontaneous ignition point of solids described in Embodiment 4 to test the spontaneous ignition point of low - melting - point solid - sulfur, including the following steps:

[0152] First, raise the furnace lid 2 through the lifting slide rod 13, fill the sample basket with the specimen sulfur, gently tap and compact it, and then add more samples until the sample basket is completely filled.

[0153] Then insert the second thermocouple sensor 6 into the center position of the specimen, and insert the third thermocouple sensor 7 into the specimen at a position 5 mm lower than the bottom end of the second thermocouple sensor 6.

[0154] After lowering the furnace lid 2 to its original position, turn on the power switch of the heating furnace. Enter the test interface on the computer control monitor 11. After setting test parameters such as sample information, air flow rate (50 mL / min), target temperature (400 °C), heating rate (0.5 °C / min), etc., start the test.

[0155] During the test, the actual state of the sample can be observed in real time through the mirror 8. When the flame detector 9 detects a flaming combustion of the sample, it transmits a signal to the computer control monitor 11. The computer control monitor 11 controls the heating furnace to stop heating, stops injecting air, opens the solenoid valve, and fills nitrogen into the furnace 1 through the nitrogen nozzle 10 until the alarm signal of the flame detector 9 disappears or the oxygen concentration analyzer shows that the oxygen concentration in the furnace has dropped below 5%. After receiving the signal, the computer control monitor 11 controls to close the solenoid valve and stop filling nitrogen, and the test ends.

[0156] After the test ends, the computer control monitor 11 automatically controls the lifting slide rod 13 to raise the furnace lid 2 to separate the specimen container from the furnace 1, and turns on the radiator blower to cool down.

[0157] The test results show that the temperature of the heating furnace 1 when the flame detector 9 detects a flaming combustion of sulfur is 216.3 °C, and this temperature is determined as the spontaneous ignition point of sulfur. The test method and device provided by the present invention effectively avoid the melting and leakage of low-melting sulfur, filling the blank of the test for the spontaneous ignition point of low-melting solids.

[0158] Example 3

[0159] Use the solid spontaneous ignition point test device described in Embodiment 4 to test the spontaneous ignition point of polyethylene, including the following steps:

[0160] First, raise the furnace lid 2 through the lifting slide rod 13, fill the sample basket with the specimen polyethylene particles, gently tap and compact them, and then add more samples until the sample basket is completely filled.

[0161] Then insert the second thermocouple sensor 6 into the center position of the specimen, and insert the third thermocouple sensor 7 into the specimen at a position 5 mm lower than the bottom end of the second thermocouple sensor 6.

[0162] After lowering the furnace lid 2 to its original position, turn on the power switch of the heating furnace. Enter the test interface on the computer control monitor 11. After setting test parameters such as sample information, air flow rate (50 mL / min), target temperature (400 °C), heating rate (0.5 °C / min), etc., start the test.

[0163] During the test, the actual state of the sample can be observed in real time through the reflector 8.

[0164] When the central temperature of the test specimen reaches 400 °C, the test ends. The computer controls the monitor 11 to stop the heating of the heating furnace, stop injecting air, raise the furnace lid 2 to separate the specimen container 4 from the furnace chamber 1, and turn on the radiator blower to cool down.

[0165] The test results show that when the temperature of the test specimen reaches 400 °C, the corresponding heating furnace temperature is 210.5 °C. This temperature is determined as the autoignition point of polyethylene.

[0166] Comparative Example 2

[0167] Using the same sample - polyethylene, test method, and test device as in Example 3, the only difference between Comparative Example 2 and Example 3 is that Comparative Example 2 only uses the second thermocouple sensor 6 inserted into the center position of the polyethylene sample to monitor the sample temperature. As a result, until the temperature of the furnace chamber 1 reaches the target temperature of 400 °C, the autoignition point of the sample is not detected, or the test result of the autoignition point is too high - 221.6 °C.

[0168] The comparison results show that the design of the dual thermocouple sensor for monitoring the sample temperature in the present invention can effectively avoid the problem that the small - density sample shrinks and detaches from the thermocouple sensor after heating, resulting in the thermocouple sensor being unable to detect the true internal temperature of the sample, and the test results are more accurate and reliable.

[0169] Example 4

[0170] Using the solid autoignition point test device described in Embodiment 4 to test the autoignition point of polyvinyl alcohol, including the following steps:

[0171] First, raise the furnace lid 2 through the lifting slide rod 13, fill the sample basket with the test specimen polyvinyl alcohol, gently tap and compact it, and then add more samples until the sample basket is completely filled.

[0172] Then insert the second thermocouple sensor 6 into the center position of the test specimen, and insert the third thermocouple sensor 7 into the test specimen at a position 5 mm lower than the bottom end of the second thermocouple sensor 6.

[0173] After lowering the furnace lid 2 to its original position, turn on the power switch of the heating furnace, enter the test interface on the computer - controlled monitor 11, set the test parameters such as sample information, air flow rate (50 mL / min), target temperature (400 °C), heating rate (0.5 °C / min), etc., and then start the test.

[0174] During the test, the actual state of the sample can be observed in real time through the reflector 8. When the central temperature of the sample reaches 400 °C, the test ends.

[0175] The computer-controlled monitor 11 controls the heating furnace to stop heating, stop injecting air, raise the furnace lid 2 to separate the sample container from the furnace chamber 1, and turn on the radiator blower to cool down.

[0176] View the temperature change curve over time. The results show that when the sample temperature starts to exceed the temperature of the heating furnace chamber 1 by 80 °C, the corresponding temperature of the heating furnace chamber 1 is 239.7 °C, and when the sample temperature reaches 400 °C, the corresponding temperature of the heating furnace chamber 1 is 355.3 °C.

[0177] During the repeated experiments, it was observed through the mirror 8 that the sample was actually in a glowing combustion state when the temperature of the heating furnace chamber 1 was 241.8 °C. It shows that it is more reasonable to supplement that the center temperature of the sample exceeds the temperature of the heating furnace chamber 1 by at least 80 °C as one of the criteria for determining the spontaneous ignition point, which can effectively avoid the problems of low accuracy and poor reliability of the test results caused by the overly single determination criterion.

[0178] In summary, the present invention provides a multi-criterion method for determining the spontaneous ignition point of solids. When any of the following states occurs, it can be determined that the spontaneous ignition point has been reached: (a) a flaming combustion phenomenon is observed; (b) the center temperature of the sample reaches 400 °C; (c) the temperature record shows that the center temperature of the sample exceeds the temperature of the heating furnace by at least 80 °C.

[0179] The present invention effectively overcomes the shortcomings of the existing methods for testing the spontaneous ignition point of solids, where the determination criteria are overly single, which may lead to low accuracy and poor reliability of the test results due to problems such as the thermocouple being separated from the center of the sample and insufficient oxygen supply during the test process. It also fills the blank in the testing of the spontaneous ignition point of low-melting-point solids, improving the test accuracy and applicability of the spontaneous ignition point of solids.

[0180] It should be noted that the terms "first", "second", and "third" in the present invention are only for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0181] In the description of the present invention, unless otherwise clearly specified and limited, terms such as "set", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected, or indirectly connected through an intermediate medium; it can be a wired connection or a wireless connection. If the connection method is not specifically described, the mature conventional means in the prior art are adopted. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0182] In the description of this specification, the description referring to the terms "some specific embodiments" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0183] Certainly, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A solid spontaneous ignition point test device, characterized in that, It includes a heating furnace, a sample container and a computer control monitor. The heating furnace includes a furnace chamber and a furnace cover located at the top of the furnace chamber. The furnace chamber and the furnace cover are detachably connected. The sample container is connected to the furnace cover by a wire and suspended in the furnace chamber; An oxygen concentration analyzer is provided in the furnace chamber. A first thermocouple sensor is provided on the inner side wall of the furnace chamber. Both the oxygen concentration analyzer and the first thermocouple sensor are connected to the computer control monitor; A transparent and visible observation window is provided at a position on the furnace cover opposite to the sample container. An air disperser connected to an external air source, a flame detector, a second thermocouple sensor and a third thermocouple sensor for monitoring the sample temperature are provided on the furnace cover. The second thermocouple sensor and the third thermocouple sensor extend into the sample to be tested in the sample container at different heights and are connected to the computer control monitor. The air disperser and the flame detector both extend into the furnace chamber and are connected to the computer control monitor.

2. The solid spontaneous ignition point testing device according to claim 1, wherein The sample container has a double-layer structure of an upper basket and a lower tray. The bottom area of the sample tray located directly below is larger than the bottom area of the sample basket located directly above.

3. The solid autoignition point testing device according to claim 1 or 2, characterized in that, A nitrogen nozzle for injecting nitrogen into the furnace chamber is further provided on the inner side wall of the furnace chamber. The nitrogen nozzle is connected to the nitrogen output pipeline of a nitrogen generator. An electromagnetic valve for controlling the on-off of the pipeline is provided on the nitrogen output pipeline. The electromagnetic valve is connected to the computer control monitor.

4. The solid spontaneous ignition point testing device according to claim 3, characterized in that, A lifting slide rod for driving the opening and closing of the furnace cover is provided on the heating furnace. A reflector for observing the situation inside the furnace chamber is provided on the lifting slide rod.

5. The solid spontaneous ignition point testing device according to claim 4, characterized in that, The observation window is made of high-temperature glass.

6. The solid spontaneous ignition point testing device according to claim 2, characterized in that, The sample basket is a cube without an upper surface folded from a stainless steel wire mesh. The sample tray is made of a stainless steel plate.

7. The solid autoignition point testing device according to claim 5 or 6, characterized in that The second thermocouple sensor is inserted into the center position of the sample. The third thermocouple sensor is inserted into the sample at a position 5 mm further down than the bottom end of the second thermocouple sensor.

8. The solid spontaneous ignition point testing device according to claim 7, wherein, A radiator is further provided on the furnace chamber. The radiator is connected to the computer control monitor.

9. The solid spontaneous ignition point testing device according to claim 8, characterized in that, The air disperser is made of a copper pipe. The copper pipe first extends downward into the furnace chamber until it is close to the inner bottom wall of the furnace chamber, then turns to one side and approaches one side wall in a coiled or wave-shaped manner. When it is close to one side wall, it turns upward and extends above the sample container, and finally turns and extends to the opposite side wall. A plurality of parallel downward-extending branches are provided at the tail end of the copper pipe. Some of the branches are located in the sample basket and some are located in the furnace chamber.

10. The solid autoignition point testing device according to claim 3, characterized in that, There are multiple nitrogen nozzles, and multiple nitrogen nozzles are arranged in pairs opposite to each other; there are multiple first thermocouple sensors, and multiple first thermocouple sensors are arranged in pairs opposite to each other.

11. A method for testing the spontaneous ignition point of a solid, characterized in that, Using the solid spontaneous ignition point test device according to any one of claims 3-10, includes the following steps: S1. Raise the furnace cover, load the sample into the sample basket, gently tap and compact it, and then add more samples until the sample basket is completely filled; S2. Insert the second thermocouple sensor into the center position of the sample, and insert the third thermocouple sensor into the sample at a position 5 mm further down than the bottom end of the second thermocouple sensor; S3. After covering the furnace with the furnace lid, turn on the heating furnace. Enter the test interface on the computer control monitor. After setting the sample information, air flow rate, target temperature, and heating rate, start the test; S4. During the test, observe the actual state of the sample in real time. When the center temperature of the sample detected by the second thermocouple sensor and the third thermocouple sensor reaches the target temperature, or the flame detector recognizes that the sample has flaming combustion, or the temperature detected by the second thermocouple sensor and the third thermocouple sensor exceeds the temperature detected by the first thermocouple sensor by 80 °C, the test ends. The heating furnace stops heating and stops injecting air. At this time, the temperature detected by the first thermocouple sensor is the autoignition temperature of the sample; When the flame detector recognizes that the sample has flaming combustion, it transmits a signal to the computer control monitor, the solenoid valve opens, and nitrogen is filled into the furnace through the nitrogen nozzle until the alarm signal of the flame detector disappears or the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace drops to a certain level, then the solenoid valve closes and stops filling nitrogen; S5. Raise the furnace lid to separate the sample container from the furnace.

12. The solid spontaneous ignition point test method according to claim 11, characterized in that, The target temperature is 400 °C; when the oxygen concentration analyzer monitors and shows that the oxygen concentration in the furnace drops below 5%, the solenoid valve closes.

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