A test device and method for electrically charged powder discharging to ignite combustible gas dust

Abstract

The application discloses a kind of charged powder discharge ignites combustible gas dust test device and method, comprising: charged powder discharge cavity, charged powder discharge cavity includes lower layer cavity, and the side of lower layer cavity is equipped with vertical long hole;Combustible gas premixing cavity, combustible gas premixing cavity includes upper layer cavity, and T-shaped sliding door is installed below upper layer cavity;Charged powder discharge mechanism, charged powder discharge mechanism is installed above lower layer cavity;Combustible dust discharge mechanism, combustible dust discharge mechanism is installed above upper layer cavity;Spark discharge induction mechanism, spark discharge induction mechanism is arranged outside lower layer cavity;Combustible gas gas distribution system, combustible gas gas distribution system is installed in the side of upper layer cavity;Insulating bottom plate is installed in the bottom of lower layer cavity.The application establishes a set of charged powder discharge ignites combustible gas dust test device and method, which can be directly realized, to provide further reference for the prevention and cure of gas dust combustion and explosion disaster.

Description

Technical Field

[0001] The present invention relates to the technical field of gas and dust explosion characteristics and risk parameter testing, and in particular to a testing device and method for charged powder discharge igniting combustible gas and dust. Background Art

[0002] Gas and dust explosions are a major safety hazard in production and daily life. Accurately understanding the critical conditions for gas and dust explosions is extremely important for preventing and controlling explosion disasters. Furthermore, modern industrial production processes increasingly involve mixtures of combustible powders and combustible gases, such as the common mixture of coal dust and gas in the coal industry, the common mixture of plastic and pharmaceutical powders and gaseous intermediates in the production and processing of organic materials, and the mixture of aluminum and magnesium metal powders and hydrogen found in emerging high-end manufacturing industries such as 3D printing. In these mixtures, because the critical ignition energy required to ignite combustible gases is low, while the energy density of combustible dust is high, explosion disasters involving gas and dust mixtures often present more complex and severe consequences than explosions involving a single gas or dust. On the other hand, electrostatic charging of powders occurs frequently during the powder processing process, which makes it easy for charges to accumulate in the powder to form charged powder. Once the charged powder is close to metal conductor materials with high curvature, such as metal protrusions in the powder transport pipeline, instrument probes inside the silo, pipeline support edges, etc., spark discharge may occur between the charged powder and the metal conductor. This electrostatic discharge spark is a potential ignition source that ignites combustibles or dust and their mixtures, inducing gas and dust explosion disasters.

[0003] Currently, testing the critical conditions for ignition of combustible gas or dust discharges primarily involves directly using a capacitor to generate sparks of varying energies through the electrode tip to ignite the combustible gas or dust, and their mixtures, and then determining the critical spark energy required for successful ignition. However, this method of directly igniting gas or dust through capacitor discharge sparks ignores the spark discharge process of charged powders caused by electrostatic charging. It is unable to determine the critical charge conditions required for spark discharge of charged powders, nor the critical charge conditions required for further ignition of combustible gas or dust. Therefore, it is impossible to accurately assess the risk of gas or dust explosion hazards caused by the powder charge itself.

[0004] Based on the above technical problems, the present invention provides a testing device and method for igniting combustible gas and dust by discharged charged powder. Summary of the Invention

[0005] The purpose of the present invention is to provide a testing device and method for igniting combustible gas and dust by charged powder discharge, so as to solve the problems existing in the prior art.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides a testing device for igniting combustible gas and dust by charged powder discharge, comprising:

[0007] A charged powder discharge cavity, the charged powder discharge cavity comprising a lower cavity, a side of which is provided with a vertical long hole;

[0008] A combustible gas premixing chamber, the combustible gas premixing chamber comprising an upper chamber, the upper chamber being installed above the lower chamber, and a T-shaped sliding door being installed below the upper chamber;

[0009] a charged powder discharging mechanism, the charged powder discharging mechanism being installed above the lower cavity;

[0010] a combustible dust discharging mechanism, the combustible dust discharging mechanism being installed above the upper cavity;

[0011] a spark discharge inducing mechanism, the spark discharge inducing mechanism being arranged outside the lower cavity, and a working end thereof extending into the lower cavity through the vertical long hole;

[0012] A combustible gas distribution system, the combustible gas distribution system being installed on a side of the upper cavity;

[0013] Wherein, an insulating bottom plate is installed at the bottom of the lower cavity.

[0014] According to the test device for igniting combustible gas and dust by charged powder discharge provided by the present invention, the charged powder discharge mechanism includes:

[0015] a conical support frame, the conical support frame being fixedly connected to the top of the lower cavity;

[0016] An insulating funnel is detachably connected to the conical support frame, the axis of the insulating funnel is collinear with the axis of the lower cavity, and the insulating funnel is used to inject charged powder into the bottom of the lower cavity to form a conical charged powder.

[0017] According to the test device for charged powder discharge igniting combustible gas and dust provided by the present invention, the combustible dust discharge mechanism includes:

[0018] A top powder plate, the upper part of the upper cavity is symmetrically connected to a support shaft, and two groups of top powder plates are provided. The two groups of top powder plates are respectively fixedly connected to the support shaft, and combustible dust is placed on the top surface of the top powder plates;

[0019] A flip motor is fixed on the side wall of the upper cavity, and the flip motor is axially connected to the support.

[0020] According to the test device for igniting combustible gas and dust by charged powder discharge provided by the present invention, the spark discharge inducing mechanism includes:

[0021] a servo push-pull rod, the servo push-pull rod being vertically fixed outside the lower cavity;

[0022] A horizontal connecting rod, the horizontal connecting rod being horizontally fixedly connected to the top end of the servo push-pull rod, a closing component being installed in the long hole, and the horizontal connecting rod passing through the closing component and extending into the lower cavity;

[0023] A spark discharge inducing electrode is fixed to the end of the horizontal connecting rod and is connected to an ammeter through an electrical conductor.

[0024] According to the test device for igniting combustible gas and dust by charged powder discharge provided by the present invention, the combustible gas distribution system includes:

[0025] An air extraction unit, comprising an air extraction pipeline, a vacuum pump, and an air extraction valve, wherein the air extraction pipeline is connected to the upper cavity, the vacuum pump is connected to one end of the air extraction pipeline, and the air extraction valve is installed on the air extraction pipeline;

[0026] The air supply unit includes a gas cylinder, an air intake pipeline and an air intake valve. The air intake pipeline is connected to the upper cavity, the gas cylinder is connected to one end of the air intake pipeline, and the air intake valve is installed on the air intake pipeline.

[0027] According to the test device for charged powder discharge igniting combustible gas and dust provided by the present invention, the sealing component includes:

[0028] Lateral limiting plates, the lateral limiting plates are symmetrically fixedly connected to the lower cavity and are located on both sides of the long hole;

[0029] a longitudinal sliding plate, the longitudinal sliding plate being slidably connected between the two sets of lateral limit plates and slidably engaged with the outer wall of the lower cavity;

[0030] The wall-away limiting plates are provided in two groups. The two groups of wall-away limiting plates are respectively fixed to the top ends of the lateral limiting plates and are arranged in a rectangular structure with the lateral limiting plates. The lateral limiting plates are limitedly matched with the longitudinal sliding plates;

[0031] Wherein, a through hole is opened on the longitudinal sliding plate, and the through hole is arranged corresponding to the long hole. The horizontal connecting rod extends into the lower cavity through the through hole.

[0032] According to the testing device for charged powder discharge ignition of combustible gas and dust provided by the present invention, a sealing cover is installed on the top of the upper cavity, and a pressure relief valve is installed on the sealing cover.

[0033] According to the testing device for charged powder discharge ignition of combustible gas and dust provided by the present invention, the material of the upper cavity and the lower cavity are both high-strength steel, and the upper cavity and the lower cavity are respectively installed with an upper transparent window and a lower transparent window, and the upper transparent window and the lower transparent window are made of quartz glass.

[0034] A test method for charged powder discharge igniting combustible gas and dust, including a test method for the critical charge of charged powder spark discharge and a test method for the critical charge of charged powder discharge igniting combustible gas or dust and their mixed cloud;

[0035] The method for testing the critical charge of charged powder spark discharge comprises the following steps:

[0036] S1. Inject charged powder with a charge of Q into the lower cavity through the charged powder discharge mechanism, allowing it to naturally accumulate on the insulating bottom plate to form a conical charged powder. Record the powder height as h. Remove the charged powder discharge mechanism and install a spark discharge inducing mechanism. Use the spark discharge inducing mechanism to adjust the vertical distance between its working end and the insulating bottom plate to ensure that it is above the charged powder and maintains a safe distance. Record this distance as H.

[0037] S2, inducing spark discharge in the charged powder, starting the spark discharge induction mechanism, causing the working end to slowly move downward at a certain speed v and approach the top of the charged powder, while monitoring the current change; if there is no significant current surge until the working end moves into the charged powder, the spark discharge induction fails; if a significant current surge is monitored during the process, the induction is successful;

[0038] S3, estimate the spark discharge energy. If the induction fails, the spark discharge energy E(Q) = 0. If the induction is successful, read the current surge time t, calculate the spark discharge arc length L = Hh-vΧt, and estimate the discharge voltage U≈EaΧL based on the air dielectric strength Ea. Estimate the energy E(Q)≈∫UI(t)dt by integrating U and the discharge current I(t) over time.

[0039] S4, change the powder charge and repeat the experiment. If the induction fails, increase the charge and repeat the above steps. If the induction is successful, reduce the charge and repeat the experiment until the minimum powder charge Qs that is successful is obtained. The corresponding energy E (Qs) is the critical spark energy Es.

[0040] The method for testing the critical charge of a charged powder discharge igniting a cloud of combustible gas or dust and a mixture thereof comprises the following steps:

[0041] S1, charged powder discharge;

[0042] S2: Pre-place combustible dust, install the upper chamber and the combustible dust discharge mechanism on the top of the lower chamber, close the T-shaped sliding door to isolate the upper and lower chambers; make the powder placement component horizontal through the combustible dust discharge mechanism, open the upper chamber sealing cover, and spread the combustible dust flat on the combustible dust discharge mechanism;

[0043] S3: Pre-mixing of combustible gas distribution. A preset amount of combustible gas is used. The upper chamber is evacuated through the combustible gas distribution system and then filled with combustible gas to normal pressure. The chamber is left to stand until the airflow subsides. The T-shaped sliding door is opened to connect the upper and lower chambers. The chamber is left to stand until the combustible gas diffuses into the lower chamber to form a combustible cloud.

[0044] S4, release the combustible dust, the combustible dust discharge mechanism rotates the powder placement component to a vertical state, and releases the combustible dust; after a delay period t id Afterwards, the dust spreads to form a combustible dust cloud;

[0045] S5, induce spark discharge of charged powder, start the spark discharge induction mechanism and combustible dust discharge mechanism to work synchronously, set the working end downward speed v= (Hh) / t id , ensure that a dust cloud is formed when the working end reaches the top of the charged powder; monitor the current change to determine whether the discharge is successful;

[0046] S6: Observe whether the combustible cloud is ignited. Observe through the lower transparent window whether the spark ignites the cloud. The formation and spread of the flame are used as the ignition judgment criteria.

[0047] S7, estimated spark discharge energy;

[0048] S8, change the powder charge and repeat the experiment: if it does not ignite, increase the charge and repeat the experiment; if it ignites, reduce the charge and repeat the experiment until the minimum powder charge Q for successful ignition is obtained ig , which corresponds to the energy E (Q ig ) is the critical ignition energy E ig .

[0049] The present invention discloses the following technical effects:

[0050] Through the combination of various mechanism modules, the present invention can directly induce charged powder spark discharge to form electrostatic discharge sparks, and further ignite combustible gas or dust and their mixtures, thereby testing the critical powder charge required for charged powder to generate spark discharge and the critical powder charge required for powder discharge sparks to ignite combustible gas or dust and their mixtures. By using the charged powder discharging mechanism, charged powders of different charges can be injected into the bottom of the charged powder explosion cavity to form a conical charged powder; by using the spark discharge inducing mechanism, the distance between the discharge electrode tip and the cone tip of the conical charged powder can be controlled, and by gradually approaching the discharge electrode tip and the charged powder cone tip, a spark discharge effect between the charged powder and the discharge electrode tip is induced, and the spark discharge current can be monitored, the critical powder charge required for the charged powder to generate spark discharge can be tested, and the spark discharge energy can be evaluated; further combined with the combustible gas premixing cavity, the combustible gas distribution system and the combustible dust discharging mechanism, combustible gas or dust and its mixture can be introduced around the charged powder to realize the ignition effect of the charged powder discharge spark on the combustible gas or dust and its mixture, thereby testing the critical powder charge required for the charged powder discharge spark to ignite the combustible gas or dust and its mixture.

[0051] The present invention is specifically used to address the risk of explosion caused by electrostatic discharge of charged powder igniting combustible gas or dust in the powder-related industry. It can induce electrostatic discharge of charged powder to form discharge sparks and ignite combustible gas or dust and their mixtures, thereby obtaining the critical powder charge required for the charged powder to generate spark discharge and the critical powder charge required for the powder discharge spark to ignite combustible gas or dust and their mixtures. The powder charge is directly used as an indicator to test the critical conditions for igniting combustible gas or dust and their mixtures, which can provide support for the accurate assessment and prevention of gas dust explosion disaster risks caused by static electricity accumulation of powder in the powder-related industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0053] Figure 1 Schematic diagram of the test device for igniting combustible gas and dust by charged powder discharge according to the present invention;

[0054] Figure 2 It is a cross-sectional view of the lower cavity of the present invention along the main view direction;

[0055] Figure 3It is a right side view of the lower cavity of the present invention;

[0056] Figure 4 This is a flow chart of the test method for igniting combustible gas and dust by charged powder discharge according to the present invention.

[0057] Among them, 1. Lower cavity; 2. Insulating bottom plate; 3. Lower transparent window; 4. Conical support frame; 5. Insulating funnel; 6. Servo push-pull rod; 7. Horizontal connecting rod; 8. Spark discharge inducing electrode; 9. Electrical conductor; 10. Ammeter; 11. Longitudinal sliding plate; 12. Lateral limit plate; 13. Wall limit plate; 14. Upper cavity; 15. Upper transparent window; 16. T-shaped sliding door; 17. Sealing cover; 18. Pressure relief valve; 19. Vacuum pump; 20. Exhaust pipeline; 21. Exhaust valve; 22. Gas cylinder; 23. Intake pipeline; 24. Intake valve; 25. Top powder plate; 26. Flip motor. DETAILED DESCRIPTION

[0058] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0059] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0060] Reference Figures 1-4 The present invention provides a testing device for igniting combustible gas and dust by charged powder discharge, comprising:

[0061] The charged powder discharge cavity comprises a lower cavity 1, and a vertical long hole is opened on the side of the lower cavity 1;

[0062] The combustible gas premixing chamber includes an upper chamber 14, which is installed above the lower chamber 1, and a T-shaped sliding door 16 is installed below the upper chamber 14;

[0063] The charged powder discharging mechanism is installed above the lower cavity 1;

[0064] Combustible dust discharge mechanism, the combustible dust discharge mechanism is installed above the upper cavity 14;

[0065] The spark discharge inducing mechanism is arranged outside the lower cavity 1, and the working end extends into the lower cavity 1 through the vertical long hole;

[0066] Combustible gas distribution system, the combustible gas distribution system is installed on the side of the upper cavity 14;

[0067] An insulating bottom plate 2 is installed at the bottom of the lower cavity 1 .

[0068] To further optimize the solution, the charged powder discharge mechanism includes:

[0069] The conical support frame 4 is fixedly connected to the top of the lower cavity 1;

[0070] The insulating funnel 5 is detachably connected to the conical support frame 4. The axis of the insulating funnel 5 is collinear with the axis of the lower cavity 1. The insulating funnel 5 is used to inject the charged powder into the bottom of the lower cavity 1 to form a conical charged powder.

[0071] Before operation, removably connect the insulating funnel 5 to the conical support frame 4 (the conical support frame 4 is fixed to the top of the lower chamber 1, ensuring that the axis of the insulating funnel 5 is collinear with the axis of the lower chamber 1). To inject charged powder, pour the charged powder into the insulating funnel 5. The funnel's guidance allows the charged powder to slide along the inner wall of the insulating funnel 5 to the bottom of the lower chamber 1. The insulating properties of the insulating funnel 5 reduce charge loss from the charged powder, and the powder naturally accumulates under the influence of gravity, eventually forming a conical charged powder pile at the bottom of the lower chamber 1. This provides a stable powder morphology for subsequent experiments (such as the interaction of the charged powder with other substances).

[0072] To further optimize the solution, the combustible dust discharge mechanism includes:

[0073] The top powder plate 25 is symmetrically connected to the support shaft above the upper cavity 14. There are two groups of top powder plates 25, which are fixedly connected to the support shaft respectively. The combustible dust is placed on the top surface of the top powder plates 25.

[0074] The flip motor 26 is fixed on the side wall of the upper cavity 14 and is axially connected to the support.

[0075] Initially, two sets of top powder-receiving plates 25 are arranged horizontally via support shafts (rotatably connected to the upper portion of the upper chamber 14), depositing combustible dust evenly across the top surfaces of the plates 25. When the combustible dust needs to be released, the flip motor 26 is activated, its output shaft rotating the support shaft, which in turn drives the two sets of top powder-receiving plates 25 to flip synchronously. As the flip angle of the top powder-receiving plates 25 increases, the combustible dust on them releases from the plates under the influence of gravity and falls into the upper chamber 14, completing the release of the combustible dust. The symmetrical arrangement of the top powder-receiving plates 25 ensures uniform dust distribution, meeting the experimental requirements for dust distribution.

[0076] Further optimization scheme, the spark discharge inducing mechanism includes:

[0077] A servo push-pull rod 6 is vertically fixed outside the lower cavity 1;

[0078] The horizontal connecting rod 7 is horizontally fixedly connected to the top of the servo push-pull rod 6, and a closing component is installed in the long hole. The horizontal connecting rod 7 passes through the closing component and extends into the lower cavity 1;

[0079] The spark discharge inducing electrode 8 is fixed to the end of the horizontal connecting rod 7 and is connected to the ammeter 10 through the electrical conductor 9 .

[0080] During operation, the servo push-pull rod 6 adjusts the height and horizontal position of the horizontal connecting rod 7 through telescopic action. The horizontal connecting rod 7 extends into the lower cavity 1 through the through hole of the closed component and the long hole of the lower cavity 1, driving the spark discharge inducing electrode 8 at the end to move in the lower cavity 1, thereby achieving precise adjustment of the electrode position. When spark discharge needs to be induced, the spark discharge inducing electrode 8 is connected to the power supply through the electrical wire 9 to generate a discharge spark. The ammeter 10 monitors the current changes during the discharge process in real time to provide electrical parameter data for the experiment. At the same time, the closed component always maintains a sealed fit with the lower cavity 1 when the horizontal connecting rod 7 moves through the sliding cooperation of the longitudinal sliding plate 11 and the lateral limit plate 12, thereby avoiding gas leakage inside the cavity and ensuring a stable discharge environment.

[0081] To further optimize the solution, the combustible gas distribution system includes:

[0082] The exhaust unit includes an exhaust pipe 20, a vacuum pump 19 and an exhaust valve 21. The exhaust pipe 20 is connected to the upper cavity 14, the vacuum pump 19 is connected to one end of the exhaust pipe 20, and the exhaust valve 21 is installed on the exhaust pipe 20;

[0083] The air supply unit includes a gas cylinder 22, an air intake pipe 23 and an air intake valve 24. The air intake pipe 23 is connected to the upper cavity 14, the gas cylinder 22 is connected to one end of the air intake pipe 23, and the air intake valve 24 is installed on the air intake pipe 23.

[0084] Before gas distribution, close the intake valve 24 and the exhaust valve 21. First, perform the exhaust operation: open the exhaust valve 21, start the vacuum pump 19, and exhaust the air in the upper chamber 14 through the exhaust pipeline 20 to form a certain vacuum degree in the chamber, and close the exhaust valve 21 after the exhaust is completed. Then, perform the gas supply operation: open the intake valve 24, and the combustible gas in the gas cylinder 22 enters the upper chamber 14 through the intake pipeline 23, and the intake amount is controlled according to the required gas concentration of the experiment, and the intake valve 24 is closed after the intake is completed. Through the coordinated operation of the exhaust and supply, the precise proportioning of the combustible gas in the upper chamber 14 is realized, which meets the needs of different experimental conditions.

[0085] Further optimization scheme, the closed assembly comprises:

[0086] The lateral limiting plates 12 are symmetrically fixedly connected to the lower chamber 1 and located on both sides of the long hole;

[0087] The longitudinal sliding plate 11 is slidingly connected between the two groups of lateral limiting plates 12 and slidingly matched with the outer wall of the lower chamber 1;

[0088] The off-wall limiting plates 13 are provided in two groups, and the two groups of off-wall limiting plates 13 are respectively fixed to the top ends of the lateral limiting plates 12 and arranged in a rectangular structure between the lateral limiting plates 12 and the lateral limiting plates 12 and the longitudinal sliding plate 11;

[0089] The longitudinal sliding plate 11 is provided with a through hole corresponding to the long hole, and the horizontal connecting rod 7 extends into the lower chamber 1 through the through hole.

[0090] When the horizontal connecting rod 7 moves under the driving of the servo push-pull rod 6, since the horizontal connecting rod 7 passes through the through hole of the longitudinal sliding plate 11, the longitudinal sliding plate 11 will slide between the two groups of lateral limiting plates 12 along with the movement of the horizontal connecting rod 7 (the lateral limiting plates 12 are symmetrically fixed to the lower chamber 1 and located on both sides of the long hole, limiting the lateral displacement of the longitudinal sliding plate 11). The off-wall limiting plates 13 and the lateral limiting plates 12 form a rectangular structure to prevent the longitudinal sliding plate 11 from being separated from the outer wall of the lower chamber 1. In this process, the longitudinal sliding plate 11 is always tightly attached to the outer wall of the lower chamber 1, and the through hole and the long hole keep corresponding, ensuring the sealing of the lower chamber 1 when the horizontal connecting rod 7 moves, avoiding the leakage of the internal gas affecting the experimental environment.

[0091] Further optimization scheme, the top of the upper chamber 14 is provided with a sealing cover 17, and the sealing cover 17 is provided with a pressure relief valve 18.

[0092] Before the experiment, a sealing cap 17 is installed on top of the upper chamber 14 to seal it, preventing internal gas leakage and external air infiltration, thus ensuring the airtightness of the experimental environment. During the experiment, if combustion, reaction, or other factors generate high pressure within the upper chamber 14, and the pressure exceeds the set threshold of the pressure relief valve 18, the valve 18 automatically opens, releasing the high-pressure gas within the chamber and reducing the internal pressure. This prevents damage to the chamber due to overpressure and ensures the safety of the equipment and the experiment. Once the pressure returns to normal, the pressure relief valve 18 closes, maintaining the chamber's seal.

[0093] Further optimization scheme, the material of the upper cavity 14 and the lower cavity 1 are both high-strength steel, and the upper transparent window 15 and the lower transparent window 3 are respectively installed on the upper cavity 14 and the lower cavity 1, and the upper transparent window 15 and the lower transparent window 3 are made of quartz glass.

[0094] Before the experiment, a sealing cap 17 is installed on top of the upper chamber 14 to seal it, preventing internal gas leakage and external air infiltration, thus ensuring the airtightness of the experimental environment. During the experiment, if combustion, reaction, or other factors generate high pressure within the upper chamber 14, and the pressure exceeds the set threshold of the pressure relief valve 18, the valve 18 automatically opens, releasing the high-pressure gas within the chamber and reducing the internal pressure. This prevents damage to the chamber due to overpressure and ensures the safety of the equipment and the experiment. Once the pressure returns to normal, the pressure relief valve 18 closes, maintaining the chamber's seal.

[0095] Upper / lower cavity 1 and transparent window working process

[0096] The upper chamber 14 and lower chamber 1 are constructed of high-strength steel, capable of withstanding the high pressure and impact loads likely to occur during experiments, ensuring the stability and safety of the chamber structure. During experiments, operators observe internal dynamics through the upper transparent window 15 (located in the upper chamber 14) and the lower transparent window 3 (located in the lower chamber 1): such as the diffusion of combustible dust in the upper chamber 14, the accumulation of charged powder in the lower chamber 1, spark discharge phenomena, and potential combustion and explosion processes. The transparent windows, made of quartz glass, are heat-resistant and highly transparent, ensuring clear observation of experimental details even in high temperatures and strong light environments, providing a visual basis for experimental recording and analysis.

[0097] A test method for charged powder discharge igniting combustible gas and dust, including a test method for the critical charge of charged powder spark discharge and a test method for the critical charge of charged powder discharge igniting combustible gas or dust and their mixed cloud;

[0098] The method for testing the critical charge of charged powder spark discharge includes the following steps:

[0099] In step S1, charged powder with a charge of Q is injected into the lower cavity 1 through the charged powder discharge mechanism, and the charged powder is naturally accumulated on the insulating bottom plate 2 to form a conical charged powder. The powder height is recorded as h. The charged powder discharge mechanism is removed, and a spark discharge inducing mechanism is installed. The spark discharge inducing mechanism is used to adjust the vertical distance between its working end and the insulating bottom plate 2 to ensure that it is above the charged powder and maintains a safe distance. This distance is recorded as H.

[0100] S2, inducing spark discharge in the charged powder, starting the spark discharge induction mechanism, causing the working end to slowly move downward at a certain speed v and approach the top of the charged powder, while monitoring the current change; if there is no significant current surge until the working end moves into the charged powder, the spark discharge induction fails; if a significant current surge is monitored during the process, the induction is successful;

[0101] S3, estimate the spark discharge energy. If the induction fails, the spark discharge energy E(Q) = 0. If the induction is successful, read the current surge time t, calculate the spark discharge arc length L = Hh-vΧt, and estimate the discharge voltage U≈EaΧL based on the air dielectric strength Ea. Estimate the energy E(Q)≈∫UI(t)dt by integrating U and the discharge current I(t) over time.

[0102] S4, change the powder charge and repeat the experiment. If the induction fails, increase the charge and repeat the above steps. If the induction is successful, reduce the charge and repeat the experiment until the minimum powder charge Qs that is successful is obtained. The corresponding energy E (Qs) is the critical spark energy Es.

[0103] The test method for the critical charge of charged powder discharge to ignite a cloud of combustible gas or dust or their mixtures comprises the following steps:

[0104] S1, charged powder discharge;

[0105] S2: Pre-place combustible dust. Install the upper chamber 14 and the combustible dust discharge mechanism on the top of the lower chamber 1. Close the T-shaped sliding door 16 to isolate the upper chamber 14 from the lower chamber 1. Use the combustible dust discharge mechanism to make the powder placement component horizontal. Open the sealing cover 17 of the upper chamber 14 and spread the combustible dust evenly on the combustible dust discharge mechanism.

[0106] S3: Pre-mix the combustible gas. A preset amount of combustible gas is used. The upper chamber 14 is evacuated through the combustible gas distribution system and then filled with combustible gas to atmospheric pressure. The mixture is allowed to stand until the airflow subsides. The T-shaped sliding door 16 is opened to connect the upper and lower chambers. The mixture is allowed to stand until the combustible gas diffuses into the lower chamber 1 to form a combustible cloud.

[0107] S4, release the combustible dust, the combustible dust discharge mechanism rotates the powder placement component to a vertical state, and releases the combustible dust; after a delay period t idAfterwards, the dust spreads to form a combustible dust cloud;

[0108] S5, induce spark discharge of charged powder, start the spark discharge induction mechanism and combustible dust discharge mechanism to work synchronously, set the working end downward speed v= (Hh) / t id , ensure that a dust cloud is formed when the working end reaches the top of the charged powder; monitor the current change to determine whether the discharge is successful;

[0109] S6, observe whether the combustible cloud is ignited, and observe through the lower transparent window 3 whether the spark ignites the cloud, and the formation and propagation of the flame are used as the ignition judgment criteria;

[0110] S7, estimated spark discharge energy;

[0111] S8, change the powder charge and repeat the experiment: if it does not ignite, increase the charge and repeat the experiment; if it ignites, reduce the charge and repeat the experiment until the minimum powder charge Q for successful ignition is obtained ig , which corresponds to the energy E (Q ig ) is the critical ignition energy E ig .

[0112] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0113] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A test method for igniting combustible gas and dust by charged powder discharge, characterized in that: The test method is based on a test device for charged powder discharge ignition of combustible gas and dust. The test device for charged powder discharge ignition of combustible gas and dust includes: A charged powder discharge cavity, the charged powder discharge cavity comprising a lower cavity (1), a side surface of the lower cavity (1) being provided with a vertical long hole; A combustible gas premixing cavity, the combustible gas premixing cavity comprising an upper cavity (14), the upper cavity (14) being installed above the lower cavity (1), and a T-shaped sliding door (16) being installed below the upper cavity (14); A charged powder discharge mechanism, the charged powder discharge mechanism being installed above the lower cavity (1); A combustible dust discharge mechanism, the combustible dust discharge mechanism being installed above the upper cavity (14); A spark discharge inducing mechanism, wherein the spark discharge inducing mechanism is arranged outside the lower cavity (1), and a working end extends into the lower cavity (1) through the vertical long hole; A combustible gas distribution system, the combustible gas distribution system being installed on a side of the upper cavity (14); Wherein, an insulating bottom plate (2) is installed at the bottom of the lower cavity (1); Test methods for charged powder discharge to ignite combustible gas and dust, including the test methods for the critical charge of charged powder spark discharge and the test methods for the critical charge of charged powder discharge to ignite combustible gas or dust and their mixed clouds; The method for testing the critical charge of charged powder spark discharge comprises the following steps: S1, injecting charged powder with a charge of Q into the lower cavity (1) through the charged powder discharge mechanism, so that it naturally accumulates on the insulating bottom plate (2) to form a conical charged powder, and recording the powder height as h; removing the charged powder discharge mechanism, installing the spark discharge inducing mechanism, and adjusting the vertical distance between its working end and the insulating bottom plate (2) through the spark discharge inducing mechanism to ensure that it is located above the charged powder and maintains a safe distance, and recording the distance as H; S2, inducing spark discharge in the charged powder, starting the spark discharge induction mechanism, causing the working end to slowly move downward at a certain speed v and approach the top of the charged powder, while monitoring the current change; if there is no significant current surge until the working end moves into the charged powder, the spark discharge induction fails; if a significant current surge is monitored during the process, the induction is successful; S3, estimate the spark discharge energy. If the induction fails, the spark discharge energy E(Q) = 0. If the induction is successful, read the current surge time t, calculate the spark discharge arc length L = Hh-vΧt, and estimate the discharge voltage U≈EaΧL based on the air dielectric strength Ea. Estimate the energy E(Q)≈∫UI(t)dt by integrating U and the discharge current I(t) over time. S4, change the powder charge and repeat the experiment. If the induction fails, increase the charge and repeat the above steps. If the induction is successful, reduce the charge and repeat the experiment until the minimum powder charge Qs that is successful is obtained. The corresponding energy E (Qs) is the critical spark energy Es. The method for testing the critical charge of a charged powder discharge igniting a cloud of combustible gas or dust and a mixture thereof comprises the following steps: S1, charged powder discharge; S2, pre-place combustible dust, install the upper cavity (14) and the combustible dust discharge mechanism on the top of the lower cavity (1), close the T-shaped sliding door (16) to isolate the upper cavity (14) and the lower cavity (1); make the powder placement component in a horizontal state through the combustible dust discharge mechanism, open the sealing cover (17) of the upper cavity (14), and spread the combustible dust flat on the combustible dust discharge mechanism; S3, pre-mixing the combustible gas, presetting the combustible gas volume, evacuating the upper cavity (14) through the combustible gas distribution system, and then filling the upper cavity (14) with the combustible gas to normal pressure, and allowing it to stand until the airflow subsides; opening the T-shaped sliding door (16) to connect the upper and lower cavities, and allowing it to stand until the combustible gas diffuses into the lower cavity (1) to form a combustible gas cloud; S4, release the combustible dust, the combustible dust discharge mechanism rotates the powder placement component to a vertical state, and releases the combustible dust; after a delay period t id Afterwards, the dust spreads to form a combustible dust cloud; S5, induce spark discharge of charged powder, start the spark discharge induction mechanism and combustible dust discharge mechanism to work synchronously, set the working end downward speed v= (Hh) / t id , ensure that a dust cloud is formed when the working end reaches the top of the charged powder; monitor the current change to determine whether the discharge is successful; S6, observe whether the combustible cloud is ignited, and observe through the lower transparent window (3) whether the spark ignites the cloud, with the formation and spread of flames as the ignition judgment standard; S7, estimated spark discharge energy; S8, change the powder charge and repeat the experiment: if it does not ignite, increase the charge and repeat the experiment; if it ignites, reduce the charge and repeat the experiment until the minimum powder charge Q for successful ignition is obtained ig , which corresponds to the energy E(Q ig ) is the critical ignition energy E ig .

2. The method for testing the ignition of combustible gas and dust by charged powder discharge according to claim 1, characterized in that: The charged powder discharging mechanism comprises: A conical support frame (4), the conical support frame (4) being fixedly connected to the top of the lower cavity (1); An insulating funnel (5) is detachably connected to the conical support frame (4), the axis of the insulating funnel (5) is collinear with the axis of the lower cavity (1), and the insulating funnel (5) is used to inject charged powder into the bottom of the lower cavity (1) to form a conical charged powder.

3. The method for testing the ignition of combustible gas and dust by charged powder discharge according to claim 1, characterized in that: The combustible dust discharging mechanism includes: A top powder plate (25) is symmetrically connected to a support shaft above the upper cavity (14), and two groups of top powder plates (25) are provided. The two groups of top powder plates (25) are respectively fixedly connected to the support shaft, and combustible dust is placed on the top surface of the top powder plates (25); A flip motor (26) is fixed on the side wall of the upper cavity (14), and the flip motor (26) is axially connected to the support.

4. The method for testing the ignition of combustible gas and dust by charged powder discharge according to claim 1, characterized in that: The spark discharge inducing mechanism comprises: A servo push-pull rod (6), the servo push-pull rod (6) being vertically fixed outside the lower cavity (1); A horizontal connecting rod (7), the horizontal connecting rod (7) is horizontally fixedly connected to the top end of the servo push-pull rod (6), a closing component is installed in the long hole, and the horizontal connecting rod (7) passes through the closing component and extends into the lower cavity (1); A spark discharge inducing electrode (8) is fixed to the end of the horizontal connecting rod (7), and the spark discharge inducing electrode (8) is connected to an ammeter (10) via an electrical conductor (9).

5. The method for testing the ignition of combustible gas and dust by charged powder discharge according to claim 1, characterized in that: The combustible gas distribution system comprises: An air extraction unit, the air extraction unit comprising an air extraction pipeline (20), a vacuum pump (19) and an air extraction valve (21), the air extraction pipeline (20) being connected to the upper cavity (14), the vacuum pump (19) being connected to one end of the air extraction pipeline (20), and the air extraction valve (21) being installed on the air extraction pipeline (20); An air supply unit, comprising a gas cylinder (22), an air intake pipeline (23) and an air intake valve (24), wherein the air intake pipeline (23) is connected to the upper cavity (14), the gas cylinder (22) is connected to one end of the air intake pipeline (23), and the air intake valve (24) is installed on the air intake pipeline (23).

6. The method for testing the ignition of combustible gas and dust by charged powder discharge according to claim 4, characterized in that: The closure assembly comprises: Lateral limiting plates (12), the lateral limiting plates (12) being symmetrically fixedly connected to the lower cavity (1) and located on both sides of the long hole; A longitudinal sliding plate (11), the longitudinal sliding plate (11) is slidably connected between the two sets of lateral limit plates (12) and slidably cooperates with the outer wall of the lower cavity (1); A wall-away limiting plate (13), wherein two groups of the wall-away limiting plates (13) are provided, and the two groups of the wall-away limiting plates (13) are respectively fixed to the top ends of the lateral limiting plates (12), and are arranged in a rectangular structure with the lateral limiting plates (12), and the lateral limiting plates (12) are in position-limiting cooperation with the longitudinal sliding plates (11); A through hole is provided on the longitudinal sliding plate (11), the through hole is arranged corresponding to the long hole, and the horizontal connecting rod (7) extends into the lower cavity (1) through the through hole.

7. The method for testing the ignition of combustible gas and dust by charged powder discharge according to claim 1, characterized in that: A sealing cover (17) is installed on the top of the upper cavity (14), and a pressure relief valve (18) is installed on the sealing cover (17).

8. The method for testing the ignition of combustible gas and dust by charged powder discharge according to claim 1, characterized in that: The upper cavity (14) and the lower cavity (1) are both made of high-strength steel. An upper transparent window (15) and a lower transparent window (3) are respectively installed on the upper cavity (14) and the lower cavity (1). The upper transparent window (15) and the lower transparent window (3) are made of quartz glass.

Images