Air curtain smoke prevention system for subway platform layer fire and use method thereof

Abstract

The application provides an air curtain smoke prevention system for subway platform layer fire, which comprises an air conditioning air supply main pipe, a platform layer air conditioning unit is connected to an air inlet of the air conditioning air supply main pipe, a first valve is arranged at one end of the air conditioning air supply main pipe close to the air inlet, an air curtain main pipe is further connected to the air conditioning air supply main pipe, an air inlet of the air curtain main pipe is located between the air inlet of the air conditioning air supply main pipe and the first valve, an air outlet of the air curtain main pipe is communicated with an air curtain branch pipe, the air curtain branch pipe is arranged at the top of a building escalator port, the air curtain branch pipe is in n-shaped structure and surrounds the outside of the building escalator port, and an air curtain air outlet is formed at the bottom of the air curtain branch pipe. Air is introduced from the air supply pipe of the air conditioning air supply system, and a strip gap air inlet is arranged around each building escalator port, so that an air curtain is formed around the building escalator port, the building escalator port area is isolated from the platform area by the air curtain, and smoke is controlled in the platform area.

Description

Technical Field

[0001] This invention belongs to the field of subway station fire protection technology, and particularly relates to an air curtain smoke prevention system and its usage method for subway platform fires. Background Technology

[0002] Subways, due to their high safety, punctuality, speed, and large capacity, have become a major mode of public transportation for commuting in large and megacities. With the increase in subway lines and passenger flow, subway operation safety has become a growing concern and presents significant challenges. Fire is a major safety hazard in subway operations, accounting for approximately 65% ​​of all safety accidents. The subway system is a large, narrow underground space, largely isolated from the atmosphere except for station entrances and ventilation shafts. Platforms, as the main waiting areas within stations, are confined spaces where passengers spend the most time. In the event of a fire on the platform, passengers can only evacuate upwards via escalators and staircases. To ensure safe passenger evacuation, the national standard "Code for Design of Subways" (GB50157-2013) stipulates that "in the event of a fire on the subway platform, a downward airflow of not less than 1.5 m / s should be ensured at the entrances of stairs and escalators from the station hall to the platform."

[0003] To meet mandatory requirements of regulations, the widely adopted smoke extraction scheme in subway fire ventilation system design involves activating the large-scale smoke extraction fans at both ends of the station, and using exhaust fans and tunnel fans for coordinated smoke extraction. The large-scale smoke extraction fans extract smoke through the smoke extraction pipes in the public area of ​​the platform, while the exhaust fans extract smoke through dedicated platform smoke extraction ducts or by opening the side smoke extraction valves above the platform screen doors and extracting smoke through the track top exhaust ducts. This coordinated smoke extraction method using exhaust fans and tunnel fans increases the total smoke extraction volume on the platform. However, during train overtaking operations, pressure fluctuations on the platform caused by piston wind in the track area can lead to insufficient air supply velocity at escalator and stairwell entrances, sometimes even resulting in backflow. This causes smoke to spread from the platform to the concourse near the fire source at escalator and stairwell entrances, affecting the evacuation of platform personnel and posing a safety hazard to the concourse area.

[0004] To address the aforementioned issues, Chinese patent CN105221180B discloses a fire-resistant partitioning method for subway platforms. This method involves promptly activating the front-end air curtain unit near the platform level; and activating the rear-end air curtain unit near the concourse level when the smoke concentration exceeds a preset value or the fire duration exceeds a preset duration, thereby assisting personnel on the platform level to evacuate to the concourse level in a timely manner. Once the evacuation is complete, the rear-end air curtain unit and the front-end air curtain unit are sequentially deactivated.

[0005] The aforementioned patent proposes installing front-end and rear-end air curtain machines at the stairwells and escalators between the platform and the concourse. The air curtain formed by the air curtain machines isolates the smoke from the platform. However, since the smoke exhaust and air supply on the platform mainly come from the stairwells and escalators, the airflow from top to bottom at the stairwells and escalators mixes with the supply and return airflow of the air curtain machines themselves, which will generate local complex vortices. This will further accelerate the mixing and diffusion of smoke at the stairwells and escalators, which is especially unfavorable for areas with high concentrations of smoke near the fire source. Summary of the Invention

[0006] Based on the technical problems existing in the background art, the present invention provides an air curtain smoke prevention system and its usage method for fires on subway platforms. Air is drawn from the air supply duct of the air conditioning system, and slotted air supply outlets are arranged around each stair and escalator entrance to form an air supply air curtain around the stair and escalator entrance. The air curtain is used to isolate the stair and escalator entrance area from the platform area, ensuring that the smoke is controlled within the platform area.

[0007] To achieve the above objectives, the present invention provides a smoke curtain system for use in subway platform fires, comprising an air conditioning main pipe installed at the top of one side of the escalator, an air inlet of the air conditioning main pipe connected to a platform air conditioning unit, a first valve at one end of the air conditioning main pipe near the air inlet, an air curtain main pipe connected to the air conditioning main pipe, the air inlet of the air curtain main pipe located between the air inlet of the air conditioning main pipe and the first valve, an air curtain branch pipe connected to the air outlet of the air curtain main pipe, the air curtain branch pipe being installed at the top of the escalator entrance, the air curtain branch pipe having an n-shaped structure and surrounding the outside of the escalator entrance; an air curtain outlet being provided at the bottom of the air curtain branch pipe, and a smoke curtain wall being attached to the inner side of the air curtain branch pipe, the length of the air curtain branch pipe being the same as that of the smoke curtain wall.

[0008] Preferably, the main air curtain pipe is equipped with a second valve, and an axial flow fan is also installed on the main air curtain pipe near the end of the branch air curtain pipe.

[0009] Preferably, the number of air curtain smoke prevention systems is the same as the number of stairwells and escalators, and they are evenly distributed at multiple stairwells and escalators. Multiple smoke detectors are installed on the top slab of the subway platform.

[0010] Preferably, the design air volume of the air curtain smoke prevention system at a single stairwell entrance is calculated according to Formula 1;

[0011] Q f =v f ×L×W formula 1,

[0012] In the formula: Q f Design the air volume for the air curtains at all stairwell and escalator entrances;

[0013] W represents the width of the air curtain outlet at the stairwell / escalator entrance;

[0014] v f Design wind speed for air curtains at stairwell and escalator entrances;

[0015] L is the horizontal length of the smoke curtain at the stairwell entrance.

[0016] Preferably, the maximum number of air curtain smoke control systems that can be opened is calculated based on the total design capacity of the multiple air curtain smoke control systems, using the formula shown in Formula 2:

[0017]

[0018] Where: n1 is the maximum number of air curtain smoke control systems that can be opened based on the total system capacity;

[0019] Q s This refers to the total air supply volume of the platform's air conditioning system.

[0020] Preferably, the maximum number of air curtain smoke prevention systems that can be opened is calculated based on the air curtain wind balance of the platform, and the calculation formula is as shown in Formula 3;

[0021]

[0022] In the formula: n2 is the maximum number of air curtain smoke control systems that can be opened based on the platform's wind balance calculation; Q p Q represents the total smoke exhaust volume during a platform fire. py The smoke exhaust volume is designed for the platform's large system; Q pr The exhaust volume of the heat exhaust fan is designed to be [Q]. sd The design smoke exhaust volume for the tunnel ventilation fan is given; α is the proportion of platform make-up air in the smoke exhaust volume of the exhaust fan; β is the proportion of platform make-up air in the smoke exhaust volume of the tunnel ventilation fan; and δ is the proportion of mechanical make-up air in the total smoke exhaust volume of the platform.

[0023] Furthermore, when n 1＞ When n = 2, the maximum number of air curtain smoke control systems that can be opened is n = 2; when n 1＜ When n2, the maximum number of air curtain smoke control systems that can be opened is n1.

[0024] This invention also claims protection for a method of using the above-mentioned air curtain smoke control system for subway platform fires, comprising the following steps:

[0025] S1: In the event of a fire on the platform level, the platform smoke exhaust system will be activated;

[0026] S2: Based on the smoke detector, locate the fire location, close the first valve on the platform level, open the second valve, and simultaneously determine the number of air curtain smoke prevention systems activated near the fire source at the escalator entrance on the platform level.

[0027] S3: Turn on the air conditioning system at the platform level and turn on the axial flow fans of the air curtain system at the corresponding stairwell and escalator entrance to form an air curtain at the stairwell and escalator entrance;

[0028] S4: After the fire is completed, the smoke exhaust system is shut down, the air conditioning supply system on the platform is shut down, the corresponding air curtain axial flow fan is shut down, the first valve is opened, and the second valve is closed.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The air curtain smoke prevention system set up in this invention selects air from the air conditioning supply system and arranges strip air curtain outlets around each stairwell and escalator entrance. The air curtain isolates the stairwell and escalator entrance area from the platform area, ensuring that the smoke is controlled within the platform area. The structure is simple, reduces energy consumption, is easy to use, and is highly practical.

[0031] (2) The air curtain smoke prevention system set up in this invention verifies the maximum number of air curtain smoke prevention systems that can be opened at the stairwell and escalator entrances based on the total capacity of the air curtain smoke prevention system and the air curtain air balance of the platform. The number of openings is selected according to the actual situation, which ensures the air balance of the platform, ensures that the platform maintains a slight negative pressure, and effectively prevents the platform smoke from overflowing from the stairwell and escalator entrances into the station hall. Attached Figure Description

[0032] Figure 1 This is a schematic plan view of an air curtain smoke prevention system for subway platform fires according to the present invention.

[0033] Figure 2 This is a plan view of an air curtain branch pipe of an air curtain smoke prevention system for subway platform fires according to the present invention.

[0034] Figure 3 This is a schematic diagram of the elevation structure of an air curtain smoke prevention system for subway platform fires according to the present invention.

[0035] Figure 4 This is a schematic diagram of the elevation structure of an air curtain smoke prevention system for subway platform fires according to the present invention.

[0036] The components include: 1. Air conditioning main supply pipe; 2. Air curtain main supply pipe; 3. Air curtain branch pipe; 4. Air curtain outlet; 5. First valve; 6. Second valve; 7. Axial flow fan; 8. Smoke curtain. Detailed Implementation

[0037] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention. Furthermore, the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0038] Example 1

[0039] An air curtain smoke control system for subway platform fires includes an air conditioning main pipe 1 installed at the top of one side of the escalator. The air inlet of the air conditioning main pipe 1 is connected to an air conditioning unit at the platform level. A first valve 5 is provided at one end of the air conditioning main pipe 1 near the air inlet. An air curtain main pipe 2 is also connected to the air conditioning main pipe 1. The air inlet of the air curtain main pipe 2 is located between the air inlet of the air conditioning main pipe 1 and the first valve 5. The air outlet of the air curtain main pipe 2 is connected to an air curtain branch pipe 3. The air curtain branch pipe 3 is installed at the top of the escalator entrance. The air curtain branch pipe 3 has an n-shaped structure and surrounds the outside of the escalator entrance. An air curtain outlet 4 is provided at the bottom of the air curtain branch pipe 3. A smoke curtain wall 8 is attached to the inner side of the air curtain branch pipe 3. The lengths of the air curtain branch pipe 3 and the smoke curtain wall 8 are the same.

[0040] In this embodiment, the main air curtain pipe 2 is provided with a second valve 6, and an axial flow fan 7 is also installed on the main air curtain pipe 2 near the end of the air curtain branch pipe 3.

[0041] Air conditioning supply main pipe 1 belongs to the air conditioning supply system, which delivers fresh outdoor air to the platform level. Air curtain main pipe 2 is connected to air conditioning supply main pipe 1. In case of fire, the first valve 5 can be closed and the second valve 6 can be opened directly to use the fresh air introduced by the air conditioning system in the air curtain smoke prevention system. The axial flow fan 7 pressurizes and delivers the air to the air curtain outlet 4. The air outlet direction is vertically downward, forming an air curtain at the stairwell and escalator entrance, isolating the smoke from the platform level from entering the stairwell and escalator entrance, and preventing it from spreading to the concourse level.

[0042] In this embodiment, the number of air curtain smoke prevention systems is the same as the number of stairwells and escalators, and they are evenly distributed at multiple stairwells and escalators. Multiple smoke detectors are installed on the top slab of the subway platform.

[0043] Smoke detectors are used to locate the source of fire, providing a basis for determining the location to open the air curtain at the entrance of stairwells and escalators.

[0044] In this embodiment, the design air volume of the air curtain smoke prevention system at a single stairwell entrance is calculated according to Formula 1;

[0045] Q f =v f ×L×W formula 1,

[0046] In the formula: Q f Design the air volume for the air curtains at all stairwell and escalator entrances;

[0047] W represents the width of the air curtain outlet at the stairwell / escalator entrance;

[0048] v fDesign wind speed for air curtains at stairwell and escalator entrances;

[0049] L is the horizontal length of the smoke curtain at the stairwell entrance.

[0050] The horizontal length L of the smoke curtain at the stairwell entrance is 18m, and the design wind speed v of the air curtain is... f Given a speed of 5 m / s and an air curtain width W of 0.15 m, the calculated Q value for a single stairwell / escalator entrance is... f The design air volume is 13.5m³. 3 / s

[0051] In this embodiment, the maximum number of air curtain smoke control systems that can be opened is calculated based on the total design capacity of the multiple air curtain smoke control systems, as shown in Formula 2:

[0052]

[0053] Where: n1 is the maximum number of air curtain smoke control systems that can be opened based on the total system capacity;

[0054] Q s This refers to the total air supply volume of the platform's air conditioning system.

[0055] The platform air conditioning supply system is designed with a total air supply volume of 55m³. 3 If the number of air curtain smoke control systems to be activated is n1 = 4, then the total number of systems to be activated is calculated based on the total system capacity.

[0056] In this embodiment, the maximum number of air curtain smoke prevention systems that can be opened is calculated based on the air curtain wind balance of the platform, and the calculation formula is as shown in Formula 3.

[0057]

[0058] In the formula: n2 is the maximum number of air curtain smoke control systems that can be opened based on the platform's wind balance calculation; Q p Q represents the total smoke exhaust volume during a platform fire. py The smoke exhaust volume is designed for the platform's large system; Q pr The exhaust volume of the heat exhaust fan is designed to be [Q]. sd The design smoke exhaust volume for the tunnel ventilation fan is given; α is the proportion of platform make-up air in the smoke exhaust volume of the exhaust fan; β is the proportion of platform make-up air in the smoke exhaust volume of the tunnel ventilation fan; and δ is the proportion of mechanical make-up air in the total smoke exhaust volume of the platform.

[0059] The platform's large-scale system is designed to have a smoke exhaust volume of Q. py 44m 3 / s, exhaust air volume Q of the exhaust fan pr 100m 3 / s, tunnel ventilation fan design exhaust volume Q sd 60m 3 / s; Under the track-top ventilation duct coordinated smoke exhaust operation mode, the proportion of platform make-up air in the smoke exhaust volume of the exhaust fan α is about 70%, and the proportion of platform make-up air in the smoke exhaust volume of the tunnel fan β is about 0%; the proportion of mechanical make-up air in the total smoke exhaust volume δ is taken as 80% of the conventional design parameter, then the number of openings of the air curtain smoke prevention system calculated by platform wind balance is n2 = 6.

[0060] In this embodiment, there are only 5 stairwells and escalators, so the air curtains at all stairwells and escalators can be opened according to the platform wind balance calculation.

[0061] In this embodiment, when n 1＞ When n = 2, the maximum number of air curtain smoke control systems that can be opened is n = 2; when n 1＜ When n2, the maximum number of air curtain smoke control systems that can be opened is n1.

[0062] In summary, in this embodiment, the maximum number of air curtain smoke control systems that can be activated simultaneously is four.

[0063] Example 2

[0064] A method for using an air curtain smoke control system for fires on subway platforms includes the following steps:

[0065] S1: In the event of a fire on the platform level, the platform smoke exhaust system is activated; the smoke exhaust system begins to exhaust smoke.

[0066] S2: Based on the smoke detector to locate the fire location, close the first valve 5 on the platform level and open the second valve 6. At the same time, determine the number of air curtain smoke prevention systems to be activated near the fire source at the escalator entrance on the platform level. Activate the corresponding air curtain smoke prevention systems at the escalator entrance near the fire source according to the actual situation on site. The actual number of activated systems shall be less than or equal to the maximum number of activated systems.

[0067] S3: Turn on the air conditioning system at the platform level and turn on the axial flow fans of the air curtain system at the corresponding stairwell and escalator entrance to form an air curtain at the stairwell and escalator entrance;

[0068] S4: After the fire is completed, the smoke exhaust system is shut down, the air conditioning supply system on the platform is shut down, the corresponding air curtain axial flow fan is shut down, the first valve 5 is opened, and the second valve 6 is closed.

[0069] The working principle of the air curtain smoke control system for subway platform fires of the present invention is as follows:

[0070] When a fire occurs, the smoke exhaust system on the subway platform is activated. Based on the location feedback from the smoke detectors, the first valve 5 is closed and the second valve 6 is opened. The fresh air from the air conditioning supply main pipe is diverted to the air curtain main pipe 2. After being pressurized by the axial flow fan, the air is discharged from the air curtain outlet 4 of the air curtain branch pipe 3. The air is discharged vertically downwards, forming an air curtain. The air curtain isolates the platform level from the area above the escalators, preventing smoke from spreading to the concourse level and accelerating the evacuation of personnel. After the fire is under control, the smoke exhaust system is shut down, the air conditioning supply system on the platform level is shut down, the corresponding axial flow fan of the air curtain is shut down, the first valve 5 is opened, and the second valve 6 is closed.

[0071] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An air curtain smoke control system for subway platform fires, comprising an air conditioning main supply pipe (1) installed at the top of one side of the escalator, characterized in that: The air inlet of the air supply main pipe (1) is connected to the air conditioning unit on the platform level. The air supply main pipe (1) is provided with a first valve (5) at one end near the air inlet. The air supply main pipe (1) is also connected to an air curtain main pipe (2). The air inlet of the air curtain main pipe (2) is located between the air inlet of the air supply main pipe (1) and the first valve (5). The air outlet of the air curtain main pipe (2) is connected to an air curtain branch pipe (3). The air curtain branch pipe (3) is set at the top of the stairwell. The air curtain branch pipe (3) has an n-shaped structure and surrounds the outside of the stairwell. An air curtain outlet (4) is opened at the bottom of the air curtain branch pipe (3). A smoke curtain (8) is attached to the inside of the air curtain branch pipe (3). The lengths of the air curtain branch pipe (3) and the smoke curtain (8) are the same. The main air curtain pipe (2) is equipped with a second valve (6), and an axial flow fan (7) is also installed on the main air curtain pipe (2) near the end of the air curtain branch pipe (3). The number of air curtain smoke prevention systems is the same as the number of stairwells and escalators, and they are evenly distributed at multiple stairwells and escalators. Multiple smoke detectors are installed on the ceiling of the subway platform.

2. The air curtain smoke control system for subway platform fires according to claim 1, characterized in that: The design air volume of the air curtain smoke prevention system at a single stairwell entrance is calculated according to Formula 1; (Official 1), In the formula: Design the air volume for the air curtains at all stairwell and escalator entrances; W The width of the air curtain outlet at the stairwell / escalator entrance; Design wind speed for air curtains at stairwell and escalator entrances; L The horizontal length of the smoke curtain at the entrance of the stairwell or escalator.

3. An air curtain smoke control system for subway platform fires according to claim 2, characterized in that: The maximum number of air curtain smoke control systems that can be opened is calculated based on the total design capacity of the multiple air curtain smoke control systems, as shown in Formula 2: (Official 2), In the formula: n 1 represents the maximum number of air curtain smoke control systems that can be opened, calculated based on the total system capacity. This refers to the total air supply volume of the platform's air conditioning system. The maximum number of air curtain smoke control systems that can be opened is calculated based on the air curtain wind balance of the platform, and the calculation formula is as shown in Formula 3. (Official 3), In the formula: n 2 represents the maximum number of air curtain smoke control systems that can be opened based on the platform's wind balance calculation. Total smoke exhaust volume during a platform fire; Design the smoke exhaust volume for the platform's large system; The exhaust volume of the heat exhaust fan is designed accordingly; Design the smoke exhaust volume for the tunnel ventilation fan; The proportion of platform makeup air in the exhaust volume of the exhaust fan; The proportion of platform make-up air in the smoke exhaust volume of tunnel ventilation fans; The proportion of mechanical makeup air in the total smoke exhaust volume of the platform; when n 1＞ n At 2 o'clock, the maximum number of air curtain smoke control systems that can be opened is: n 2; when n 1＜ n At 2 o'clock, the maximum number of air curtain smoke control systems that can be opened is: n 1.

4. A method of using an air curtain smoke control system for subway platform fires as described in any one of claims 1-3, characterized in that, Includes the following steps: S1: In the event of a fire on the platform level, the platform smoke exhaust system will be activated; S2: Based on the smoke detector, locate the fire location, close the first valve (5) on the platform floor, open the second valve (6), and at the same time determine the number of air curtain smoke prevention systems that are activated near the fire source at the escalator entrance on the platform floor. S3: Turn on the air conditioning system at the platform level and turn on the axial flow fans of the air curtain system at the corresponding stairwell and escalator entrance to form an air curtain at the stairwell and escalator entrance; S4: After the fire is completed, the smoke exhaust system is shut down, the air conditioning supply system on the platform is shut down, the corresponding air curtain axial flow fan is shut down, the first valve (5) is opened, and the second valve (6) is closed.

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