Dry powder ejection system and fire engine

Abstract

Dry powder ejection system that includes: a dry powder fluidization tank (1); a high-pressure gas source (2) communicating with the dry powder fluidization tank (1) in an adjustable pressure manner; a dry powder ejection device (3) communicating with the dry powder fluidization tank (1) for ejecting a fluidized dry powder gas flow; a blow-assisted device (4) configured to supply a blow-assisted gas flow at a predetermined pressure to the dry powder ejection device (3) to meet a predetermined ejection pressure required by the dry powder ejection device (3); a weighing sensor (5) configured to measure a weight of the dry powder fluidization tank (1); an alarm device configured to transmit alarm information; and a vehicle-mounted control device (6) in communication with the weighing sensor (5) and configured to calculate an optimal filling weight of the corresponding dry powder fluidization tank (1) according to a type of the received dry powder fire extinguishing agent input from the outside, to trigger the alarm device to issue an alarm when the weight measured by the weighing sensor (5) reaches the optimal filling weight.

Description

[0001] This application is based on and claims priority from Chinese Patent Application No. 201910392622.6 and Chinese Patent Application No. 201920679368.3, filed on May 13, 2019, the entire contents of both of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the field of fire protection and, in particular, to a dry powder ejection system and a firefighting vehicle. For the prior art, reference is made to DE 195 34 406 C1, SU 1 180 005 A1, and US Pat. No. 3,567,136 A. GENERAL STATE OF THE ART

[0003] With the development of the city and the congestion of urban populations, society has placed great emphasis on fire protection for high-rise buildings, fire protection for large buildings, and fire protection for petrochemical equipment. To ensure the survival and safety of public property, aerial fire engines have been predominantly used for firefighting. Aerial fire engines are equipped with aerial and firefighting equipment and can perform aerial fire extinguishing or rescue operations in the event of a fire. Aerial fire engines mainly include aerial platform fire engines, aerial ejection fire engines, and aerial ladder fire engines.

[0004] To deal with complex fires, the state-of-the-art aerial firefighting vehicle usually performs fire extinguishing treatment using a dry powder fire extinguishing agent. The typical ejection process includes the following steps: 1. Supplying gas to a high-pressure nitrogen storage cylinder under reduced pressure → 2. Fluidizing dry powder in a fluidizing tank → 3. Opening a dry powder tank outlet valve → 4. Allowing a two-phase dry powder nitrogen flow to enter a conveying pipeline → 5. Supplying the two-phase dry powder nitrogen flow to a dry powder ejector for ejection → 6. Injecting the two-phase dry powder nitrogen flow into a large-scale fire extinguishing location. SUMMARY

[0005] According to the inventors' research, it was found that for step 1 in the above ejection process, a nitrogen storage cylinder with a pressure value of not more than 1.5 MPa is generally used to supply nitrogen at a constant pressure to the fluidization tank for fluidizing the dry powder. Based on this, a tank body of the fluidization tank is generally designed according to a working pressure of 1.6 MPa. Such a working pressure is sufficient for the conventional dry powder firefighting vehicle, and the delivery pipeline from the fluidization tank to the ejection device is short and has basically no head, thereby reducing the overall pressure loss of the delivery pipeline.In addition, since the length and direction of the delivery pipeline on the conventional dry powder firefighting vehicle have been determined before it leaves the manufacturing plant, the dry powder arriving at the ejection device has sufficient ejection kinetic energy accordingly as long as the pressure in the fluidization tank meets the requirements.

[0006] For aerial fire trucks with a certain drop height (usually greater than 30 meters), the delivery pipeline of the dry powder ejection system is long, the drop height is large, and the pipeline diameter and direction change situations are complicated. Furthermore, with the change in the lifting status of the boom or ladder of the aerial fire truck, the drop height and pipeline diameter, as well as the direction change complexity of the delivery pipeline of the dry powder ejection system, increase. Consequently, the prior art aerial fire trucks suffer from the problem of insufficient discharge capability caused by insufficient blowing pressure of the dry powder ejection system.

[0007] For the technical problem of insufficient ejection ability caused by insufficient blowing pressure, if the pressure of constant pressure nitrogen supplied to the fluidization tank is increased, the design value of the working pressure of the fluidization tank will be increased, and the tank body thickness of the fluidization tank and the pipeline wall thickness of the conveying pipeline will be significantly increased, which will greatly increase the overall weight and cost of the dry powder ejection system and currently restrict the development of the aerial firefighting vehicle for higher fire fighting height.

[0008] For step 2 in the above ejection process, existing experiments show that the filling ratio of the fire extinguishing agent has a significant influence on the ejection characteristic, and the dry powder fire extinguishing agents with different physical properties usually have a reasonable filling ratio range, which corresponds to two types: when the filling ratio of the fire extinguishing agent in the fluidization tank is lower than the range, the supply amount and supply strength of the dry powder fire extinguishing agent are insufficient, and it is therefore difficult to achieve qualified fire extinguishing efficiency; when the filling ratio of the fire extinguishing agent in the fluidization tank is higher than the range, the storage amount of the propellant gas in the fluidization tank is insufficient, which consequently affects the transportation of the fire extinguishing agent to the bottom of the fluidization tank and prolongs the release process of the fire extinguishing agent;In addition, the driving pressure is lower in the middle and later stages of the fire extinguishing agent release stage, and therefore powerless powder ejection and pulsating powder transport are likely to occur.

[0009] In view of this, the material level height of filling materials in the dry powder fluidization tank is mostly observed by visual inspection in the dry powder ejection system of the prior art firefighting vehicle to determine the filling ratio of the dry powder fluidization tank. For dry powder with micrometer-sized particles, different models and batches of dry powder and different filling or storage modes may affect the volume occupied by the dry powder in the fluidization tank. Consequently, the filling ratio of the dry powder cannot be accurately measured by the determination method based on the filling height, resulting in the ejection characteristics of the two-phase dry powder-nitrogen flow provided by the dry powder ejection system not achieving optimal ejection efficiency.

[0010] Regarding step 5 of the above ejection process, based on the existing industry standard "GA39-2016 Fire Truck, Fire Fighting Requirement and Test Method", the effective ejection rate (i.e., the dry powder ejection transport rate) of the dry powder ejection device is the most important index for measuring and evaluating the dry powder ejection system. The effective ejection rate is defined as the mass change of the fluidization tank within a unit time. The index is mainly obtained by dividing a weight difference of the fluidization tank in the initial state and the final state (where the final state mainly refers to the case where the pressure in the fluidization tank is reduced to 0.5 MPa as a determination standard) by an ejection duration measured with a stopwatch, so that the average value of the ejection rate is obtained to serve as the evaluation index.

[0011] According to the inventors' research, it was found that the efficiency of dry powder injection for large-scale fire extinguishing depends on the content of the fire extinguishing agent. The direct evaluation basis for determining whether continuous injection is necessary is the effective injection rate (unit: kg / s) of the dry powder, rather than the indirect evaluation index, that is, the pressure reduction state of the dry powder tank. Although the dry powder pressure is still high, if the discharged dry powder is small and has insufficient delivery strength, it is fundamentally useless to continue discharge, resulting in the waste of both powder and nitrogen. Therefore, existing firefighting vehicles with dry powder discharge systems have the common disadvantage of lacking precise determination and control of the discharge cutoff time.

[0012] Accordingly, the present disclosure provides a dry powder ejection system and a firefighting vehicle that could solve the problem of insufficient blowing pressure of a dry powder ejection system of a boom firefighting vehicle. Many technical effects produced by the preferred technical solution among many technical solutions provided by the present disclosure are described in detail below.

[0013] In one aspect of the present disclosure, a powder ejection system is provided. The dry powder ejection system includes: a dry powder fluidization tank; a high-pressure gas source communicating with the dry powder fluidization tank in an adjustable-pressure manner; a dry powder ejection device communicating with the dry powder fluidization tank for ejecting a fluidized dry powder gas flow; and a blow-assist device configured to deliver a blow-assist gas flow at a predetermined pressure to the dry powder ejection device to ensure a predetermined ejection pressure required by the dry powder ejection device.

[0014] In some embodiments, the blow-assisted device includes: a blow-assisted conduit communicating with the dry powder fluidization tank and the dry powder ejection device through communicating conduits, and configured to mix the dry powder gas flow and the blow-assisted gas flow and cause the mixed gas to flow to the dry powder ejection device.

[0015] In some embodiments, the blow-assisted apparatus includes: a first conduit connected to the communicating conduit on one side of the dry powder fluidization tank for ejecting the dry powder gas flow; and a second conduit having an inlet portion and an outlet portion, the inlet portion configured to introduce the blow-assisted gas flow, a centerline of the outlet portion being parallel to a centerline of the first conduit, and the outlet portion configured to cause the blow-assisted gas flow to pass through the second conduit to have the same flow direction as that of the dry powder gas flow.

[0016] In some embodiments, the first conduit is jacketed outside the outlet portion, or the outlet portion is jacketed outside the first conduit; and wherein the one of the first conduit and the outlet portion disposed on the outside is provided with an opening to insert the one of the first conduit and the outlet portion disposed on the inside.

[0017] In some embodiments, the centerline of the first conduit and the centerline of the outlet section are collinear.

[0018] In some embodiments, the one of the first conduit and the outlet portion located on the outside is provided with a variable diameter conduit portion, and the variable diameter conduit portion is connected to the communicating conduit on one side of the dry powder ejection device to prevent the blow-assisted gas flow from flowing back from the first conduit.

[0019] In some embodiments, the flow surface of the variable diameter pipe section gradually changes with the flow direction.

[0020] In some embodiments, the first conduit is jacketed outside the outlet section and provided with a first variable diameter taper-expansion conduit section, the first variable diameter conduit section is connected to the communicating conduit on one side of the dry powder ejector; and an outlet of the outlet section is positioned in a taper region of the first variable diameter conduit section.

[0021] In some embodiments, an inlet diameter of the first variable diameter piping section is D1, a throat diameter of the variable diameter piping section is D2, an outlet diameter of the first variable diameter piping section is D3, a length of the tapered portion of the first variable diameter piping section is L1, a length of an expanding portion of the first variable diameter piping section is L2, a diameter of the second piping is d1, a length of a part of the outlet portion entering the first variable diameter piping section is L3, and a length of a part of the outlet portion not entering the tapered portion is L4, where D1, D2, D3, d1, L1, L2, L3, and L4 satisfy the following conditions: D3=(1.2~1.5)*D1; D2=(0.7~0.9)*D1; L1=(3~5)*D1; L2=(0.8~1.1)*D1; L3=(0.2~0.3)*L1; d1=(0.2~0.4)*D1; and L4=(6-10)*d1.

[0022] In some embodiments, the first conduit is jacketed within the outlet section; the outlet section is provided with a second variable diameter taper-expansion conduit section; the second variable diameter conduit section is connected to the communicating conduit on one side of the dry powder ejector; and an outlet of the first conduit is positioned in a taper region of the second variable diameter conduit section.

[0023] In some embodiments, an outlet diameter of the second variable diameter piping section is D5, an inlet diameter of the second variable diameter piping section is D6, a length of the second variable diameter piping section is L5, a diameter of the first piping is D7, a diameter of the second piping is d2, and a length from the outlet of the first piping to an outlet of the variable diameter piping section is L6, where D5, D6, D7, d2, L5, and L6 satisfy the following conditions: D5=D7; D6=(1.4~1.8)*D5; L5=(3~5)*D5; d2=(0.3~0.55)*D5; and L6=(0.4-0.6)*L5.

[0024] In some embodiments, the blow-assisted device further includes: an electronically controlled pressure reducing valve disposed between the blow-assisted conduit and the high pressure gas source and configured to control a pressure of the blow-assisted gas flow.

[0025] In some embodiments, the blow-assisted device further includes: a pressure sensor configured to measure an ejection pressure of an inlet of the dry powder ejection device; wherein the electronically controlled pressure reducing valve is configured to adjust the pressure of the blow-assisted gas flow according to a difference between the predetermined ejection pressure and the ejection pressure.

[0026] In some embodiments, the blow-assisted device further includes: a length sensor configured to measure a length value of a portion of the communicating pipeline between the dry powder fluidization tank and the dry powder ejection device; an angle sensor configured to measure an inclination angle of the portion of the communicating pipeline with respect to a horizontal plane; and wherein the electronically controlled pressure reducing valve is configured to adjust the pressure of the blow-assisted gas flow according to pressure loss of the portion of the communicating pipeline determined based on the length value and a change value of the angle.

[0027] According to the invention, the dry powder ejection system further includes: a weighing sensor configured to measure a weight of the dry powder fluidization tank; an alarm device configured to transmit alarm information; and a vehicle-mounted control device in communication with the weighing sensor, configured to calculate an optimal filling weight of the corresponding dry powder fluidization tank according to a type of the received dry powder fire extinguishing agent input from the outside, to trigger the alarm device to issue an alarm when the weight measured by the weighing sensor reaches the optimal filling weight.

[0028] In some embodiments, the dry powder ejection system further includes: a dry powder tank inlet valve configured at the dry powder filling port of the dry powder fluidization tank to control a flow of the dry powder filled into the dry powder fluidization tank; and wherein the vehicle-mounted controller, in communication with the dry powder tank inlet valve, is configured to cause the dry powder tank inlet valve to stop filling the dry powder when the weight measured by the weighing sensor reaches the optimal filling weight.

[0029] In some embodiments, the dry powder ejection system further includes: a dry powder tank outlet valve disposed on a communicating conduit between the dry powder fluidization tank and the dry powder ejection device for controlling fluid connection and fluid disconnection of the communicating conduit; wherein the vehicle-mounted control device, in communication with the dry powder tank outlet valve, is configured to calculate an effective dry powder ejection rate according to a real-time weight of the dry powder fluidization tank measured by the weighing sensor, and to cause the dry powder tank outlet valve to disconnect the communicating conduit when the calculated effective dry powder ejection rate is lower than an allowable minimum ejection rate corresponding to the grade of dry powder fire suppressant.

[0030] The present disclosure further provides a firefighting vehicle incorporating the dry powder ejection system described above.

[0031] Based on the above technical solution, the embodiments of the present disclosure can therefore achieve at least one of the following advantageous technical effects: The problem of insufficient blowing pressure of the dry powder discharge system of the aerial fire truck, especially the aerial fire truck with a drop height of more than 30 meters, and the long-distance delivery pipeline is solved by the blowing-assisted device without changing the rated working pressure of the dry powder fluidization tank of the existing dry powder fire truck. Thanks to the blowing-assisted device provided by the present application, the conventional dry powder fire truck could increase the blowing pressure, implement combined fire extinguishing with the aerial fire truck, and better cope with complex firefighting scenarios such as high-rise fire protection.Furthermore, the present application can automatically adjust the pressure of the blow-assisted gas flow by measuring the pressure loss of the delivery pipeline at different arm positions or measuring the inlet pressure of the dry powder ejection device, thereby ensuring the efficiency of the blow-assisted device and improving the fire-fighting capability of the aerial firefighting vehicle.

[0032] The real-time filling ratio of the dry powder fluidization tank is calculated by weighing the dry powder fluidization tank, calculating the corresponding optimal filling weight according to the type of dry powder fire extinguishing agent, and reminding an operator through the alarm device to carry out the optimal filling of the dry powder fire extinguishing agent in the filling process of the dry powder fire extinguishing agent, thereby ensuring the fire extinguishing efficiency of the dry powder fire extinguishing agent.

[0033] The effective dry powder ejection rate of the dry powder fluidization tank is calculated by weighing the dry powder fluidization tank, and the ejection of the dry powder fire extinguishing agent is actively shut down when the effective dry powder ejection rate is insufficient, thereby improving the economic efficiency of using the dry powder fire extinguishing agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings described herein are used to facilitate understanding of the present disclosure and are incorporated in and constitute a part of the present application. The schematic embodiments of the present disclosure and their description are used merely to explain the present disclosure, but do not constitute undue limitations on the present disclosure. In the accompanying drawings: is Fig. 1 is a schematic structural diagram of a dry powder ejection system according to an embodiment of the present disclosure; is Fig. 2 is a schematic structural diagram of a blow-assisted piping in a dry powder ejection system according to an embodiment of the present disclosure; and is Fig. 3 is a schematic structural diagram of a blow-assisted piping in a dry powder ejection system according to another embodiment of the present disclosure. Reference symbols:

[0035] 1: Dry powder fluidization tank; 2: High pressure gas source; 3: Dry powder ejection device; 4: Blow-assisted device, 41: Blow-assisted piping, 411: First piping, 412: Second piping, 412a: Inlet section; 412b: Outlet section, 413: Orifice, 414a: First flange, 414b: Second flange, 415: Partition plate, 4151: Vent hole; 42: Electronically controlled pressure reducing valve; 5: Weighing sensor; 51: pressure sensor, 52: length measuring sensor, 53: angle measuring sensor; 6: vehicle-mounted control device, 61: display operation platform; 71: Dry powder tank inlet valve, 72: Dry powder tank outlet valve; and 8: external powder feed valve. DETAILED DESCRIPTION

[0036] Exemplary embodiments of the present invention are described in detail below with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and in no way constitutes any limitation on the present disclosure and application or its uses. The present disclosure may be embodied in many different ways and is not limited to the embodiments described herein. The embodiments are provided so that this disclosure is thorough and complete, and so that the scope of the present disclosure will be fully understood by those skilled in the art.It is understood that unless otherwise specified, the relative arrangement of parts and steps, composition of materials, numerical expressions and numerical values ​​illustrated in the embodiments are to be considered as exemplary only and are not to be construed as limitations.

[0037] "First," "second," and similar words do not indicate order, number, or importance; they are used merely to distinguish different parts. "Comprise" or "contain" and other similar words mean that elements appearing before the word cover elements listed after the word, but do not exclude the possibility of covering other elements. "Up," "down," "left," "right," or the like are used merely to indicate a relative positional relationship. If the absolute position of a described object changes, the relative positional relationship may also change accordingly.

[0038] When the present disclosure describes a specific device as being positioned between a first device and a second device, an intermediate device may or may not be present between the specific device and the first device or the second device. When the specific device is described as being connected to another device, the specific device may be directly connected to the other device and may not include the intermediate devices, and may not be directly connected to the other device and the intermediate device.

[0039] All terms used in this disclosure (including technical or scientific terms) have the same meaning as those commonly understood by one of ordinary skill in the art to which this disclosure pertains, unless specifically defined otherwise. It should be understood that terms defined, for example, in a general dictionary should be interpreted as having meanings consistent with the meanings in the context of the prior art and should not be interpreted in an idealized or extremely formal sense, unless expressly defined herein.

[0040] Technologies, processes and equipment known to the person skilled in the art may not be discussed in detail, but where applicable, the technologies, processes and equipment should be considered part of the specification.

[0041] With reference to Fig. 1 to Fig. 3, the present disclosure provides, in some embodiments, a dry powder ejection system. The dry powder ejection system includes: a dry powder fluidization tank 1; a high-pressure gas source 2 in communication with the dry powder fluidization tank 1 in an adjustable-pressure manner; a dry powder ejection device 3 in communication with the dry powder fluidization tank 1 for ejecting a fluidized dry powder gas flow; and a blow-assist device 4 configured to deliver a blow-assist gas flow at a predetermined pressure to the dry powder ejection device 3 to ensure a predetermined ejection pressure required by the dry powder ejection device 3.

[0042] The dry powder fluidization tank 1 is configured to produce a two-phase flow dry powder propellant fire extinguishing agent. In the process of producing the fire extinguishing agent, the dry powder is first charged into the dry powder fluidization tank 1. Then, the high-pressure gas source 2 is pressurized and supplies gas to the dry powder fluidization tank 1. The dry powder is fluidized in the dry powder fluidization tank 1 by the propellant gas at the appropriate pressure, thereby forming the dry powder fire extinguishing agent for blowing.

[0043] The high-pressure gas source 2 may use a high-pressure gas storage cylinder to supply gas, and may also use a high-pressure gas station to supply gas. To achieve a better fire extinguishing effect, the gas in the high-pressure gas source 2 may be nitrogen, carbon dioxide, or inert gas, and the like, with stable chemical properties. The dry powder ejection device 3 is configured to introduce the dry powder fire extinguishing agent into a firefighting site at a specific ejection area and ejection speed, and generally includes a dry powder monitor, a dry powder gun, and the like.

[0044] According to the standards of existing related dry powder firefighting vehicles, the gas supply pressure in the process of supplying gas to the dry powder fluidization tank 1 through the high-pressure gas source 2 is generally not higher than 1.5 MPa. Therefore, the tank body thickness of the existing dry powder fluidization tank 1 is generally designed according to the working pressure of 1.6 MPa, which is higher than the maximum gas supply pressure, to ensure the safety of the equipment in the dry powder fluidization process. Based on this, the dry powder ejection system of the existing dry powder firefighting vehicle mainly includes the dry powder fluidization tank 1, the high-pressure gas source 2, the dry powder ejection device 3, and a conveying pipeline.

[0045] However, for the aerial fire truck, especially the aerial fire truck with the drop height of more than 30 meters, due to the huge drop height, the significant extension of the conveying pipeline and the complicated diameter and direction change situations, the existing gas supply pressure of 1.5 MPa could not meet the blowing pressure requirement of the dry powder ejection device 3, which affects the ejection characteristic of the dry powder ejection device 3.

[0046] Based on this, in the present application, the ejection pressure required by the dry powder ejection device 3 is satisfied by introducing the blow-assisted gas flow through the blow-assisted device 4 without changing the tank body thickness of the dry powder fluidization tank 1, the gas supply pressure and the high-pressure gas source 2, and the thickness of the conveying pipeline.

[0047] Furthermore, the predetermined discharge pressure required by the dry powder discharge device 3 changes with the change in the model of the dry powder discharge device 3; and different deployment and setup states of the conveying pipeline during the firefighting operation result in different pressure losses of the dry powder fire extinguishing agent during the transport process. Consequently, the blow-assisted device 4 could guide the blow-assisted gas flow at the predetermined pressure to the dry powder discharge device 3 based on the predetermined discharge pressure required by the dry powder discharge device 3 and, in the case of considering the pressure loss during the transport process of the dry powder fire extinguishing agent.

[0048] The blow-assisted device further includes a blow-assisted piping 41 that communicates with the dry powder fluidization tank 1 and the dry powder ejection device 3, respectively, through communicating piping. The blow-assisted piping 41 is capable of mixing the dry powder gas flow and the blow-assisted gas flow and causing the mixed gas to flow to the dry powder ejection device 3.

[0049] As a specific implementation of the blow-assisted device 4, the blow-assisted piping 41 between the dry powder fluidization tank 1 and the dry powder ejection device 3 is connected by communicating piping at two ends. For convenience of description, the communicating piping established between the blow-assisted piping 41 and the dry powder fluidization tank 1 is referred to as "the dry powder fluidization tank 1-side communicating piping." The communicating piping established between the blow-assisted piping 41 and the dry powder fluidization tank 3 is therefore referred to as "the device 3-side communicating piping."

[0050] In order to overcome the drop height of the aerial firefighting vehicle and the pressure loss of the dry powder extinguishing agent in the conveying pipeline, the blow-assisted pipeline 41 is configured to introduce the blow-assisted gas flow, which should have a pressure higher than that of the dry powder gas provided by the communicating pipeline on one side of the dry powder fluidization tank 1, so that the mixed blow-assisted gas flow and the dry powder gas flow could meet the pressure requirements of the dry powder ejection device.

[0051] Those skilled in the art must prevent pressure loss during the mixing process of the gas flow as much as possible in the mixing process of the two gas flow streams, especially when the gas pressure is required after mixing. In view of this, the piping 41 includes: a first piping 411 connected to the communicating piping on one side of the dry powder fluidization tank 1 for ejecting the dry powder gas flow; and a second piping 412 having an inlet portion 412a and an outlet portion 412b, the inlet portion 412a being configured to introduce the blow-assisted gas flow, a center line of the outlet portion 412b being parallel to a center line of the first piping 411, and the outlet portion 412b being configured to cause the blow-assisted gas flow to pass through the second piping 412 to have the same flow direction as that of the dry powder gas flow.

[0052] The inlet section 412a and the outlet section 412b are divided by the second piping 412, and the division depends on whether the piping section is used for gas intake or exhaust. The division between the inlet section 412a and the outlet section 412b does not require the angle between the inlet section 412a and the outlet section 412b to be a right angle, and does not require the presence of another intermediate piping section for gas flow transition between the inlet section 412a and the outlet section 412b.

[0053] The first piping 411 for ejecting the dry powder gas flow and the outlet portion 412b of the second piping 412 for ejecting the blow-assisted gas flow have the same gas flow direction, which could prevent the pressure loss caused by different flow directions of the two gas flow streams to maximize the kinetic energy of the blow-assisted gas flow. The first piping 411 and the second piping 412, whose flow directions are collinear, may be arranged in parallel. In this case, a mixing piping may be additionally arranged on the common downstream side of the first piping 411 and the second piping 412 to receive the dry powder gas flow and the blow-assisted gas flow and fully mix the two gas flow streams to converge.

[0054] Of course, the first pipe 411 and the second pipe 412 may be sheathed as shown in Fig. 2 to Fig. 3. Specifically, the first piping 411 is sheathed outside the outlet portion 412b, or the outlet portion 412b is sheathed outside the first piping 411; and, of the first piping 411 and the outlet portion 412b, the one located on the outside is provided with an opening 413 for inserting the one located on the inside of the first piping 411 and the outlet portion 412b.

[0055] When the first piping 411 and the second piping 412 are arranged in a jacket relationship, the first piping 411 for ejecting the dry powder gas flow should keep the flow direction unchanged to prevent dry powder from settling and pressure loss caused by piping twisting. Based on this, as described in Fig. 2, the first conduit 411 introduces the second conduit 412 through the opening 413 formed in the conduit wall, and the outlet portion 412 of the second conduit 412 is sheathed into the first conduit 411 in a turning manner, thereby maintaining the flow direction before and after mixing the dry powder gas flow. As shown in Fig. 3, the second piping 412 introduces the first piping 411 through the opening 413 formed in the flow direction by the first piping 411, and the blow-assisted gas flow turns through the angle between the outlet portion 412b and the inlet portion 412a and is mixed with the dry powder gas flow around the first piping 411, thereby ensuring that the flow direction of the dry powder gas flow remains unchanged.

[0056] Further, in order to evenly mix the blow-assisted gas flow and the dry powder gas flow, a center line of the first piping 411 and a center line of the outlet portion 412b may be configured to be collinear.

[0057] Further, in order to prevent the blow-assisted gas flow with higher pressure from flowing back from the first piping 411, the one located on the outside of the first piping 411 and the outlet portion 412b is provided with a variable diameter piping portion, the variable diameter piping portion being connected to the communicating piping on one side of the dry powder ejection device 3 to prevent the blow-assisted gas flow from flowing back from the first piping 411.

[0058] For those skilled in the art, based on a continuity equation, the velocity and pressure of the gas flow in the pipeline are influenced by the flow area in the pipeline: In the case where frictional resistance is not considered, if the flow area of ​​the pipeline increases, the velocity of the gas flow increases and the pressure of the gas flow increases. Therefore, in the present application, a reasonable pressure change is formed at the outlet of the blow-assisted gas flow by adjusting the variable-diameter pipeline section and utilizing the change in the flow area of ​​the pipeline, and the blow-assisted gas flow maintains the flow direction toward the dry powder ejection device 3, thereby preventing the blow-assisted gas flow from flowing back from the first pipeline 411.The variable-diameter pipeline section can change the flow area of ​​the pipeline sections with different radii, but the pipeline sections with different radii communicate directly with each other, generating a larger amount of protruding expansion area, thereby causing a large pressure loss. Consequently, the flow area of ​​the variable-diameter pipeline section also changes smoothly with the flow direction.The smoothly changing variable diameter pipeline section can not only reduce the pressure loss caused by the overhanging expansion of the pipeline, but also effectively reduce the increase of turbulence intensity when the mixed gas flow with blowing assistance and the dry powder gas flow flow through the variable diameter pipeline section, thereby reducing the energy dispersion of the mixed gas flow in the subsequent transportation process.

[0059] With reference to Fig. 2, in some embodiments, the first conduit 411 is jacketed outside the outlet portion 412b and provided with a first variable-diameter tapered-expanded conduit portion; the first variable-diameter conduit portion is connected to the communicating conduit on one side of the dry powder ejection device 3; and an outlet of the outlet portion 412b is positioned in a tapered region of the first variable-diameter conduit portion. The first variable-diameter conduit portion refers to the conduit portion along the flow direction where the gas flow first passes through the conduit portion with a gradually reduced flow area and then passes through the conduit portion with a gradually expanded flow area.

[0060] When the first piping 411 is sheathed outside the outlet portion 412b, the flow-assisted gas flow serves as a center flow to be surrounded by the dry powder gas flow. At this time, the first variable-diameter taper-expansion piping section is provided and connected to the communicating piping on one side of the dry powder ejection device 3, thereby ensuring the transportation process that the mixed blow-assisted gas flow and the dry powder gas flow flowing to the dry powder ejection device 3 are uniform and smooth.

[0061] Additionally, the outlet of the outlet section 412b is positioned at the tapered portion of the first variable-diameter piping section, and the pressure difference created by the first variable-diameter piping section is used for drainage, effectively preventing the blow-assisted gas flow positioned at the center from returning to the inlet of the variable-diameter piping section. Specifically, a positive pressure gradient caused by the tapered portion in the first variable-diameter piping section allows the blow-assisted gas flow to continuously flow to a lower-pressure region to prevent backflow of the blow-assisted gas flow. After the blow-assisted gas flow and the dry powder gas flow pass through a throat of the first variable-diameter piping section,the blow-assisted gas flow and the dry powder gas flow are well mixed, and the pressurization is carried out gradually by a negative pressure gradient caused by an expanding section in the first variable-diameter pipeline section, such that the mixed gas flow reaches a pressure value corresponding to the sum of the predetermined ejection pressure of the dry powder ejection device 3 and the subsequent pipeline pressure loss.

[0062] In order to reduce the turbulence intensity generated by the dry powder gas flow in the high-speed blow-assisted process of the blow-assisted gas flow and to prevent the blow-assisted gas flow from flowing back to the inlet of the first variable diameter piping section, the first variable diameter piping section is further configured as follows: an inlet diameter of the first variable-diameter piping section is D1, a throat diameter of the variable-diameter piping section is D2, an outlet diameter of the first variable-diameter piping section is D3, a length of the tapered portion of the first variable-diameter piping section is L1, a length of an expanding portion of the first variable-diameter piping section is L2, a diameter of the second piping is d1, a length of a part of the outlet portion entering the first variable-diameter piping section is L3, and a length of a part of the outlet portion not entering the tapered portion is L4, where D1, D2, D3, d1, L1, L2, L3, and L4 satisfy the following conditions: D3=(1.2-1.5)*D1; D2=(0.7-0.9)*D1; L1=(3~5)*D1; L2=(0.8~1.1)*D1; L3=(0.2~0.3)*L1; d1=(0.2~0.4)*D1; and L4=(6~10)*d1.

[0063] It should be noted that the inlet diameter D1, the throat diameter D2 and the outlet diameter D3 of the first variable diameter piping section and the diameter d1 of the second piping 412 all refer to the inner diameters of the corresponding piping.

[0064] With reference to Fig. 3, in other embodiments, the first conduit 411 is encased within the outlet section 412a, the outlet section 412b has a second tapered variable diameter conduit section connected to the communicating conduit on one side of the dry powder ejector 3, and an outlet of the first conduit 411 is positioned in a tapered region of the second variable diameter region.

[0065] As in Fig. As shown in Figure 3, when the first piping 411 is encased within the outlet portion 412b, the first piping 411 and the outlet portion 412b are mutually connected and fixed by a first flange 414a provided on a central portion of the first piping 411 and a second flange 414b provided on an end face of the opening 413 of the second piping 412. A portion of the first piping 411 inserted into the outlet portion 412b can be supported by a partition plate 415 in the outlet portion 412b, thereby forming a blow-assisted gas flow outlet with an annular gap between the variable-diameter piping portion and the first piping 411.Further, a vent hole 4151 is provided around the partition plate 415 such that the blow-assisted gas flow enters from an inlet portion 412a, passes through the vent hole 4151, and is evenly ejected along the gradually tapered inner wall of the outlet portion 412b, so that a blow-assisted gas flow function is achieved on the dry powder gas flow.

[0066] In order to ensure the uniform and smooth conveying process of the mixed blow-assisted gas flow and the dry powder gas flow and to guarantee that the blow-assisted gas flow does not flow back to the inlet of the variable diameter pipeline, the variable diameter pipeline section can be further configured as follows: an outlet diameter of the second variable diameter piping section is D5, an inlet diameter of the second variable diameter piping section is D6, a length of the second variable diameter piping section is L5, a diameter of the first piping 411 is D7, a diameter of the second piping is d2, and a length from the outlet of the first piping 411 to an outlet of the second variable diameter piping section is L6, where D5, D6, D7, d2, L5, and L6 satisfy the following conditions: D5=D7; D6=(1.4~1.8)*D5; L5=(3~5)*D5; d2=(0.3~0.55)*D5; and L6=(0.4-0.6)*L5.

[0067] It should be noted that the outlet diameter D5 and the inlet diameter D6 of the second variable diameter piping section, the diameter D7 of the first piping 411 and the diameter d2 of the second piping all refer to the inner diameters of the corresponding pipings.

[0068] In some embodiments, in order to control the pressure of the blow-assisted gas flow to cause the pressure of the mixed blow-assisted gas flow and dry powder gas flow to meet the ejection pressure requirement of the dry powder ejection device 3, the blow-assisted device 4 further includes: an electronically controlled pressure reducing valve 42 disposed between the blow-assisted conduit 41 and the high pressure gas source 2 and configured to control the pressure of the blow-assisted gas flow.

[0069] In some embodiments, the blow-assisted device 4 may further include, as a mode of adjusting the blow-assisted gas flow, a pressure sensor configured to measure an ejection pressure of an inlet of the dry powder ejection device 3. The electronically controlled pressure reducing valve 42 may thus be configured to reduce the pressure of the blow-assisted gas flow according to a difference between the predetermined ejection pressure and the ejection pressure.

[0070] In this setting mode, the vehicle-mounted control device 6 outputs an electrical signal according to a deviation between a measured value P1 of the pressure sensor 51 and the predetermined ejection pressure P2 of the dry powder ejection device 3, and adjusts the opening degree of the electronically controlled pressure reducing valve 42 to control the pressure P3 of the blow-assist gas flow to cause P1 to be greater than or equal to P2 so that the blowing pressure of the dry powder gas flow at the end of the conveying piping on one side of the dry powder ejection device 3 satisfies the predetermined ejection pressure of the dry powder ejection device 3.

[0071] In other embodiments, as another way of adjusting the blow-assisted gas flow, the blow-assisted gas flow device 4 may further include: a length measuring sensor 52 configured to measure a length value of a portion of the communicating piping between the dry powder fluidization tank 1 and the dry powder ejection device; and an angle measuring sensor 53 configured to measure an inclination angle of the communicating piping portion with respect to a horizontal plane. The electronically controlled pressure reducing valve 42 may thus be configured to adjust the pressure of the blow-assisted gas flow according to the pressure loss of the communicating piping portion determined based on the length value and a change value of an angle.The part of communicating piping may herein be a part having a drop height of the communicating piping from the dry powder fluidization tank to the dry powder ejection device, for example a section of communicating piping positioned on a support arm or ladder of the aerial firefighting vehicle.

[0072] Therefore, in the adjustment mode, the vehicle-mounted control device 6 calculates a pressure loss Pb of the conveying pipeline in real time through a calculation module of the vehicle-mounted control device 6 according to a conveying pipeline condition determined by the length measuring sensor 52 and the angle measuring sensor 53 and an empirical formula between the pipeline condition and the pressure loss of the pipeline. And the vehicle-mounted control device 6 outputs the electrical signal by combining it with the predetermined ejection pressure P2 of the dry powder ejection device to cause the electronically controlled pressure reducing valve 42 to control the pressure P3 of the blow-assisted gas flow to be equal to (1.1-1.3)*(Pb+P2).Based on this, by calibrating a linear relationship between the electrical signal output from a vehicle-mounted computer and the pressure of the blow-assisted gas flow of the electronically controlled pressure reducing valve 42 in advance, the pressure P3 of the blow-assisted gas flow can be automatically controlled.

[0073] According to the invention, the dry powder ejection system further includes: a weighing sensor 5 configured to measure a weight of the dry powder fluidization tank 1; an alarm device configured to transmit alarm information; and a vehicle-mounted control device 6 in communication with the weighing sensor 5, configured to calculate an optimal filling weight of the corresponding dry powder fluidization tank 1 according to the type of the received dry powder fire extinguishing agent input from the outside, to trigger the alarm device to issue an alarm when the weight measured by the weighing sensor reaches the optimal filling weight.

[0074] After determining the optimal filling ratio of different dry powder ejection devices 3 for dry powder fire retardants with different specifications through a cold spray test conducted in advance, the optimal loading mass corresponding to dry powder fire retardants with different specifications can be set in the vehicle-mounted control device 6. Based on this, the vehicle-mounted control device 6 can automatically indicate the corresponding preferred filling ratio and allowable loading mass as long as the correct types of dry powder fire extinguishing agents are input.

[0075] During the filling process of the dry powder fluidization tank 1, the weighing sensor 5 can accurately detect the real-time filling mass of the dry powder fire extinguishing agent in the dry powder fluidization tank 1 and feed it back to the vehicle-mounted control device 6 in real time. The vehicle-mounted control device 6 can display the real-time filling mass on a display operation board 61 for an operator's reference. Of course, the operator can also be reminded by the alarm information from the alarm device.Based on this, even if the model of the dry powder fire extinguishing agent is changed in the subsequent dry powder filling operation, the vehicle-mounted control device 6 is capable of carrying out the optimal filling of different models of dry powder fire extinguishing agents by the operator through the display operation board 61 or the alarm device as long as the correct type of dry powder fire extinguishing agent is input, thereby causing the dry powder ejection device to obtain better fire extinguishing efficiency.

[0076] In some embodiments, automatically controlling the filling process of the dry powder fluidization tank 1 with the dry powder further includes: a dry powder tank inlet valve 71 disposed at the dry powder filling port of the dry powder fluidization tank 1 and configured to control a flow of the dry powder filled into the dry powder fluidization tank 1. The vehicle-mounted control device 6 is connected to the dry powder tank inlet valve 71 by communication and further configured to control the dry powder tank inlet valve 71 to stop the filling of the dry powder when the weight measured by the weighing sensor reaches the optimal filling mass.

[0077] In some embodiments, the dry powder ejection system further includes a dry powder tank outlet valve 72 disposed on a communicating pipeline between the dry powder fluidization tank 1 and the dry powder ejection device 3, and configured to control the fluid connection and disconnection of the communicating pipeline. The vehicle-mounted control device is communicatively connected to the dry powder tank outlet valve 72 and further configured to calculate an effective dry powder ejection rate according to a real-time weight of the dry powder fluidization tank 1 calculated by the weighing sensor 5, and to close the dry powder tank outlet valve 42 to disconnect the communicating pipeline when the calculated effective dry powder ejection rate is less than a minimum allowable ejection rate corresponding to the type of dry powder fire extinguishing agent.

[0078] The effective discharge rate is the dry powder discharge mass within a unit of time (unit: kg / s), which reflects the delivery rate of the fire extinguishing agent and is an important performance index of the dry powder fire extinguishing system. In current evaluations, in order to facilitate the detection process, the dry powder deposition in the dry powder delivery pipeline is often neglected. The mass change of the dry powder tank within a unit of time serves as the dry powder discharge rate and also serves as the effective discharge rate.

[0079] The minimum allowable discharge rate depends on the type of dry powder fire extinguishing agent and is a threshold value of the effective discharge rate set according to the fire extinguishing performance, that is to say, if the dry powder discharge rate is smaller than the minimum allowable discharge rate, the continuous discharge of the dry powder fire extinguishing agent has fundamentally failed to achieve the valuable fire extinguishing effect and wastes a large amount of dry powder and blow-assisted gas.

[0080] Unlike the existing calculation method that relies on pressure sensing in the dry powder fluidization tank 1 and averages the effective discharge rate through the initial and final states, through the cooperation of the dry powder tank outlet valve 72 and the weighing sensor 5, the vehicle-mounted controller 6 could calculate the effective discharge rate of the dry powder in real time and actively stop the transport of the dry powder gas flow through the dry powder tank outlet valve 72 when the calculated dry powder discharge rate is smaller than the minimum allowable discharge rate, thereby preventing continuous discharge of the dry powder fire extinguishing agent in the low fire extinguishing value state at the final discharge state and reducing waste of dry powder and nitrogen.

[0081] The present disclosure further provides a firefighting vehicle incorporating the dry powder ejection system described above.

[0082] The embodiments of the dry powder ejection system of the present disclosure are further described with reference to the accompanying drawings.

[0083] As in Fig. 1, which is a schematic structural diagram of a dry powder ejection system according to an embodiment of the present disclosure, the dry powder ejection device mainly includes a dry powder fluidization tank 1, a high-pressure gas source 2, and a dry powder ejection device 3. According to an embodiment of the present disclosure, a flow of blow-assisted gas flow is additionally introduced from the high-pressure gas source 2 based on the embodiment, and the blow-assisted gas flow is introduced into the dry powder gas flow from the communicating piping between the dry powder fluidization tank 1 and the dry powder ejection device 3, thereby increasing the pressure of the dry powder fire extinguishing agent entering the dry powder ejection device.

[0084] As shown in dotted line parts in Fig. As shown in Figure 1, the electronically controlled pressure reducing valve 42, the pressure sensor 51, the length measuring sensor 52, and the angle measuring sensor 53 are each connected to the vehicle-mounted control device 6 by communication, so that the vehicle-mounted control device 6 can precisely control the pressure of the blow-assisted gas flow through the opening degree of the electronically controlled pressure reducing valve 42. In addition, the weighing sensor 5 and the display operation board 61 are each connected to the vehicle-mounted control device 6 by communication, and the vehicle-mounted control device 6 can obtain the real-time weight of the dry powder fluidization tank 1 in real time, so that the dry powder filling mass in the dry powder filling process and the effective ejection rate in the dry powder fire extinguishing agent ejection process are controlled, and operation options are displayed and provided to the operator through the display operation board 61. Fig. 1 further shows a first power supply valve 8 connected to the outlet of the blow-assisted piping 41. The external power supply valve 8 is configured to supply additional dry powder to the mixed dry powder fire extinguishing agent when the effective discharge rate of the mixed blow-assisted gas flow and dry powder gas flow does not meet the requirement. The external power supply valve 8 could increase the effective discharge rate without changing the existing dry powder discharge system. Fig. 2 and Fig. 3 are schematic structural diagrams of two blow-assisted pipelines in a dry powder ejection system according to embodiments of the present disclosure, wherein Fig. Figure 2 shows that a first pipeline is sheathed outside an outlet section of a second pipeline, and Fig.Figure 3 shows that a first pipeline is encased within an outlet portion of a second pipeline. Based on the above technical solution, the embodiments of the present disclosure can therefore achieve at least one of the following advantageous technical effects: The embodiment of the present disclosure solves the problem of insufficient blowing pressure of the dry powder ejection system of the aerial firefighting vehicle, especially the aerial firefighting vehicle with a drop height of more than 30 meters and a long-distance conveying pipeline, through the blowing-assisted device 4, without changing the rated working pressure of the dry powder fluidization tank 1 of the existing dry powder firefighting vehicle. Thanks to the blowing-assisted device 4 provided by the present application, the conventional dry powder firefighting vehicle could increase its blowing pressure, implement a combined firefighting operation with the aerial firefighting vehicle, and better cope with complex firefighting scenes such as high-rise building fire protection.

[0085] The embodiment of the present disclosure can automatically adjust the pressure of the blow-assisted gas flow by measuring the pressure loss of the conveying pipeline at different boom positions or by measuring the inlet pressure of the dry powder ejection device 3, thereby ensuring the efficiency of the blow-assisted device 4 and improving the fire-fighting capability of the aerial firefighting vehicle.

[0086] The embodiment of the present disclosure calculates the real-time filling ratio of the dry powder fluidization tank 1 by weighing the dry powder fluidization tank, calculating the corresponding optimal filling weight according to the type of the dry powder fire extinguishing agent, and reminds an operator through the alarm device to perform the optimal filling of the dry powder fire extinguishing agent in the filling process of the dry powder fire extinguishing agent, thereby ensuring the fire extinguishing efficiency of the dry powder fire extinguishing agent.

[0087] The embodiment of the present disclosure calculates the effective dry powder ejection rate of the dry powder fluidization tank 1 by weighing the dry powder fluidization tank 1, and actively shuts off the ejection of the dry powder fire extinguishing agent when the effective dry powder ejection rate is insufficient, thereby improving the economy of using the dry powder fire extinguishing agent.

[0088] So far, the embodiments of the present invention have been described in detail. In order not to obscure the concepts of the present disclosure, some details known in the prior art are omitted. Those skilled in the art will fully understand how to implement the technical solution disclosed herein according to the above description.

[0089] Although some specific embodiments of the present disclosure are illustrated in detail by the examples, those skilled in the art should understand that the above examples are merely illustrative and do not intend to limit the scope of the present disclosure. Those skilled in the art should understand that the above embodiments may be modified, or some technical features may be substituted with equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is disclosed by the appended claims.

Claims

A dry powder ejection system comprising: a dry powder fluidization tank (1); a high-pressure gas source (2) communicating with the dry powder fluidization tank (1) in an adjustable-pressure manner; a dry powder ejection device (3) communicating with the dry powder fluidization tank (1) for ejecting a fluidized dry powder gas flow; a blow-assist device (4) configured to supply a blow-assist gas flow at a predetermined pressure to the dry powder ejection device (3) to meet a predetermined ejection pressure required by the dry powder ejection device (3); a weighing sensor (5) configured to measure a weight of the dry powder fluidization tank (1); an alarm device configured to transmit alarm information;anda vehicle-mounted control device (6) in communication with the weighing sensor (5) and configured to calculate an optimal filling weight of the corresponding dry powder fluidization tank (1) according to a type of the received dry powder fire extinguishing agent input from the outside, to trigger the alarm device to issue an alarm when the weight measured by the weighing sensor (5) reaches the optimal filling weight.; The dry powder ejection system according to claim 1, wherein the blow-assisted device (4) comprises: a blow-assisted pipeline (41) communicating with the dry powder fluidization tank (1) and the dry powder ejection device (3) through communicating pipelines, and configured to mix the dry powder gas flow and the blow-assisted gas flow and cause the mixed gas to flow to the dry powder ejection device (3). The dry powder ejection system according to claim 2, wherein the blow-assisted piping (41) comprises:a first piping (411) connected to the communicating piping on one side of the dry powder fluidization tank (1) for ejecting the dry powder gas flow; anda second piping (412) having an inlet portion (412a) and an outlet portion (412b), the inlet portion (412a) configured to introduce the blow-assisted gas flow, a centerline of the outlet portion (412b) being parallel to a centerline of the first piping (411), and the outlet portion (412b) configured to cause the blow-assisted gas flow passing through the second piping (412) to have a flow direction same as that of the dry powder gas flow. The dry powder ejection system according to claim 3, wherein the first conduit (411) is jacketed outside the outlet portion (412b), or the outlet portion (412b) is jacketed outside the first conduit (411); and wherein the one on the outside of the first conduit (411) and the outlet portion (412b) is provided with an opening (413) for introducing the one on the inside of the first conduit (411) and the outlet portion (412b). Dry powder ejection system according to claim 4, wherein the centerline of the first conduit (411) and the centerline of the outlet section (412b) are collinear. The dry powder ejection system according to claim 4, wherein, of the first piping (411) and the outlet portion (412b), the one located on the outside is provided with a variable diameter piping portion, and the variable diameter piping portion is connected to the communicating piping on one side of the dry powder ejection device (3) to prevent the blow-assisted gas flow from flowing back from the first piping (411). The dry powder ejection system of claim 6, wherein a flow area of ​​the variable diameter piping section gradually changes with the flow direction. The dry powder ejection system according to claim 3, wherein the first conduit (411) is jacketed outside the outlet portion (412b) and is provided with a first variable diameter taper-expansion conduit portion, the first variable diameter conduit portion is connected to the communicating conduit on one side of the dry powder ejection device (3); and an outlet of the outlet portion (412b) is positioned in a taper region of the first variable diameter conduit portion. The dry powder ejection system according to claim 8, wherein an inner diameter of the first variable diameter piping section is D1, a throat diameter of the first variable diameter piping section is D2, an outlet diameter of the first variable diameter piping section is D3, a length of the tapered portion of the first variable diameter piping section is L1, a length of an expanding portion of the first variable diameter piping section is L2, a diameter of the second piping (412) is d1, a length of a portion of the outlet portion entering the first variable diameter piping section is L3, and a length of a portion of the outlet portion not entering the tapered portion is L4, where D1, D2, D3, d1, L1, L2, L3, and L4 satisfy the following conditions: D3=(1.2-1.5)*D1; D2=(0.7-0.9)*D1; L1=(3~5)*D1; L2=(0.8~1.1)*D1; L3=(0.2~0.3)*L1; d1=(0.2~0.4)*D1;and L4=(6~10)*d1.; The dry powder ejection system according to claim 3, wherein the first conduit (411) is encased within the outlet portion (412b); the outlet portion (412b) is provided with a second tapered conduit portion of variable diameter; the second variable diameter conduit portion is connected to the communicating conduit on one side of the dry powder ejection device (3); and an outlet of the first conduit (411) is positioned in a tapered region of the second variable diameter conduit portion. The dry powder ejection system according to claim 10, wherein an outlet diameter of the second variable diameter piping section is D5, an inlet diameter of the second variable diameter piping section is D6, a length of the second variable diameter piping section is L5, a diameter of the first piping (411) is D7, a diameter of the second piping (412) is d2, and a length from the outlet of the first piping (411) to an outlet of the variable diameter piping section is L6, where D5, D6, D7, d2, L5 and L6 satisfy the following conditions: D5=D7; D6=(1.4~1.8)*D5; L5=(3~5)*D5; d2=(0.3~0.55)*D5; and L6=(0.4-0.6)*L5. The dry powder ejection system of claim 2, wherein the blow-assisted device (4) further comprises:an electronically controlled pressure reducing valve (42) disposed between the blow-assisted conduit (41) and the high pressure gas source (2) and configured to control a pressure of the blow-assisted gas flow. The dry powder ejection system of claim 12, wherein the blow-assisted device (4) further comprises:a pressure sensor (51) configured to measure an ejection pressure of an inlet of the dry powder ejection device (3);wherein the electronically controlled pressure reducing valve (42) is configured to adjust the pressure of the blow-assisted gas flow according to a difference between the predetermined ejection pressure and the ejection pressure. The dry powder ejection system according to claim 12, wherein the blow-assisted device (4) further comprises: a length measuring sensor (52) configured to measure a length value of a communicating piping portion between the dry powder fluidization tank (1) and the dry powder ejection device (3); an angle measuring sensor (53) configured to measure an inclination angle of the communicating piping portion with respect to a horizontal plane; and wherein the electronically controlled pressure reducing valve (42) is configured to adjust the pressure of the blow-assisted gas flow according to pressure loss of the communicating piping portion determined based on the length value and a change value of an angle. The dry powder ejection system according to claim 1, further comprising: a dry powder tank inlet valve (71) installed at the dry powder filling port of the dry powder fluidization tank (1) and configured to control a flow of the dry powder filled into the dry powder fluidization tank (1); and wherein the vehicle-mounted control device (6) having the dry powder tank inlet valve (71) is configured to cause the dry powder tank outlet valve (71) to stop filling the dry powder when the weight measured by the weighing sensor (5) reaches the optimal filling weight. The dry powder ejection system of claim 1, further comprising: a dry powder tank outlet valve (72) disposed on a communicating pipeline between the dry powder fluidization tank (1) and the dry powder ejection device (3) and configured to control fluid connection and fluid disconnection of the communicating pipeline; wherein the vehicle-mounted control device (6) in communication with the dry powder tank outlet valve (72) is configured to calculate an effective dry powder ejection rate according to a real-time weight of the dry powder fluidization tank (1) calculated by the weighing sensor (5), and to close the dry powder tank outlet valve (72) to disconnect the communicating pipeline when the calculated effective dry powder ejection rate is less than a minimum allowable ejection rate corresponding to the grade of dry powder fire extinguishing agent. A firefighting vehicle comprising the dry powder ejection system according to any one of claims 1 to 16.

Images