Roadway fire sealing device

Abstract

The invention provides a roadway fire sealing device, relates to the technical field of roadway safety, and aims to solve the problem of untight sealing of roadway fire. The roadway fire sealing device comprises a plurality of sealing units which are arranged at intervals in the length direction of a roadway. Each plugging unit comprises a dry powder spraying assembly and an inflatable air bag capable of being unfolded in the width direction of the roadway, the surface of each inflatable air bag is covered with fireproof cloth, and the fireproof cloth is arranged to be located on the side, facing the working face, of the corresponding inflatable air bag. The plugging tightness can be improved.

Description

Technical Field

[0001] This application relates to the field of tunnel safety technology, and more specifically, to a tunnel fire sealing device. Background Technology

[0002] In coal mining operations with roadways left along the goaf, the roadway space is prone to spontaneous combustion fires due to factors such as broken coal pillars, oxidation of residual coal, and ventilation leaks. If the fire area is not sealed off in time, the fire will spread rapidly, causing major safety accidents such as gas explosions and the spread of toxic gases. Existing fire sealing technologies have significant shortcomings: (1) Response delay: In the traditional closure process, it is necessary to manually move sandbags and build airtight walls. It usually takes more than 30 minutes from the discovery of the fire to the start of closure, which may easily miss the best time to control the fire.

[0003] (2) Poor sealing effect: The artificially constructed sealed structure is prone to gaps and has a high air leakage rate, making it difficult to completely cut off the oxygen supply to the fire area, which leads to the risk of reignition.

[0004] (3) High safety risks: Personnel need to enter the vicinity of the fire area to work, facing threats such as high temperatures, toxic gases (such as carbon monoxide), and collapses, which can easily cause casualties. Summary of the Invention

[0005] The first aspect of this application aims to provide a roadway fire sealing device to solve the technical problem of inadequate sealing of existing roadway fires.

[0006] The roadway fire sealing device provided in the first aspect of this application includes a plurality of sealing units, which are arranged at intervals along the length of the roadway; each sealing unit includes a dry powder injection assembly and an inflatable airbag that can be deployed along the width of the roadway, the surface of the inflatable airbag being covered with a fireproof cloth, which is arranged on the side of the inflatable airbag facing the working face.

[0007] The beneficial effects of the roadway fire sealing device proposed in this application are: By installing dry powder injection components and inflatable airbags in each sealing unit, and utilizing the ability of the inflatable airbags to adapt to irregular tunnel walls, gaps between the inflatable airbags and the tunnel walls are reduced or even eliminated, significantly reducing the air leakage rate. Combined with fireproof cloth and dry powder, the oxygen supply to the fire area can be blocked more thoroughly, and the sealing tightness is significantly improved.

[0008] Optional technical solutions also include an airbag storage cavity and an airbag positioning cavity disposed in the tunnel. The airbag storage cavity and the airbag positioning cavity are located on opposite sidewalls of the tunnel. When the inflatable airbag is in a contracted state, it is located in the airbag storage cavity. When the inflatable airbag is fully deployed, one side of the inflatable airbag is located in the airbag storage cavity, and the other side is located in the airbag positioning cavity. The inflatable airbag is configured to drive the fireproof cloth to adhere to the same sidewall of the airbag positioning cavity and the airbag storage cavity.

[0009] In an optional technical solution, the roadway fire sealing device further includes an airbag traction mechanism, which is located at the top of the roadway fire sealing device, and the inflatable airbag is driven to the power output end of the airbag traction mechanism.

[0010] In an optional technical solution, the airbag traction mechanism includes a winding assembly and a traction rope. The winding assembly is disposed in the airbag positioning cavity, one end of the traction rope is connected to the winding assembly, and the traction rope is configured to be wound around the winding assembly.

[0011] In an optional technical solution, the roadway fire sealing device further includes a support frame, which is detachably connected to the top of the roadway, the airbag storage chamber, and the airbag positioning chamber, and the top of the inflatable airbag is slidably connected to the support frame.

[0012] In an optional technical solution, the roadway fire sealing device further includes a first airbag sensor and a second airbag sensor. The first airbag sensor and the second airbag sensor are electrically connected to the controller. The first airbag sensor is disposed in the airbag storage cavity, and the second airbag sensor is disposed in the airbag positioning cavity. The first airbag sensor and the second airbag sensor are configured to both detect the inflatable airbag and then send a signal to the controller to control the inflation module connected to the inflatable airbag to inflate the inflatable airbag.

[0013] In an optional technical solution, the dry powder spraying assembly includes a dry powder spraying nozzle, which is configured to spray dry powder toward the edge region of the deployed inflatable airbag.

[0014] In an optional technical solution, the sealing unit includes two inflatable airbags spaced apart along the length of the tunnel; each sealing unit includes four sets of dry powder injection components, and the opposite sides of each inflatable airbag are configured to be sprayed by the dry powder injection components.

[0015] In an optional technical solution, the dry powder spraying assembly further includes a dry powder detection sensor, which is used to detect the thickness of the dry powder sprayed onto the inflatable airbag.

[0016] In an optional technical solution, the roadway fire sealing device further includes a working face temperature sensor and a gas sensor, which are configured to be installed in the roadway and spaced 5m to 8m apart from the sealing unit. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments or background art of this application, the drawings used in the description of the embodiments or background art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the roadway fire sealing device provided in the embodiments of this application.

[0019] Figure 2 This is a schematic diagram of the structure of the roadway fire sealing device provided in the embodiment of this application in the inflated airbag deployment state.

[0020] Explanation of reference numerals in the attached figures: 10-Inflatable airbag; 20-Dry powder injection assembly; 21-Dry powder injection nozzle; 22-Dry powder detection sensor; 31-Airbag storage chamber; 32-Airbag positioning chamber; 33-Tunnel; 41-Winding assembly; 50-Support; 51-Slide rail; 61-First airbag sensor; 62-Second airbag sensor; 71-Working face temperature sensor; 72-Gas sensor; 81-Controller; 82-Ground monitoring platform. Detailed Implementation

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0022] Example 1: Figure 1 This is a schematic diagram of the structure of the roadway fire sealing device provided in the embodiments of this application. Figure 2 This is a schematic diagram of the structure of the roadway fire sealing device provided in the embodiment of this application in the deployed state of the inflatable airbag. Figures 1-2 As shown, the roadway fire sealing device provided in Embodiment 1 of this application includes multiple sealing units, which are arranged at intervals along the length of the roadway 33. Each sealing unit includes a dry powder spraying assembly 20 and an inflatable airbag 10 that can be deployed along the width of the roadway 33. The surface of the inflatable airbag 10 is covered with a fireproof cloth (not shown), which is located on the side of the inflatable airbag 10 facing the working face.

[0023] By setting up a dry powder injection assembly 20 and an inflatable airbag 10 in each sealing unit, and utilizing the ability of the inflatable airbag 10 to adapt to the irregular tunnel wall 33, the gap between the inflatable airbag 10 and the tunnel wall 33 is reduced or even eliminated, significantly reducing the air leakage rate. Combined with fireproof cloth and dry powder, the oxygen supply to the fire area can be blocked more thoroughly, and the sealing tightness is significantly improved.

[0024] In this embodiment, the sealing unit can be set at a preset cross-section position along the goaf, for example, one sealing unit can be set every 150m to 250m, more specifically, one sealing unit can be set every 200m. In this embodiment, the fireproof cloth can be folded, remaining folded when the inflatable airbag 10 is not deployed. The folded area can be only 1 / 10 of the deployed area, facilitating pre-installation. The inflatable airbag 10 is made of oil-resistant and flame-retardant rubber material, with an inflation pressure of 0.3MPa to 0.5MPa. Of course, the inflatable airbag 10 can be more than one airbag; it can be multiple airbags connected continuously.

[0025] like Figure 1 and Figure 2 As shown, optionally, it also includes an airbag storage cavity 31 and an airbag positioning cavity 32 disposed in the tunnel 33. The airbag storage cavity 31 and the airbag positioning cavity 32 are located on opposite side walls of the tunnel 33. When the inflatable airbag 10 is in a contracted state, it is located in the airbag storage cavity 31. When the inflatable airbag 10 is fully deployed, one side of the inflatable airbag 10 is located in the airbag storage cavity 31, and the other side is located in the airbag positioning cavity 32. The inflatable airbag 10 is configured to drive the fireproof cloth to adhere to the side walls of the same side of the airbag positioning cavity 32 and the airbag storage cavity 31.

[0026] By setting up an airbag positioning cavity 32 and an airbag storage cavity 31 on opposite sidewalls of the roadway 33, not only can the space occupied by the sealing unit in the roadway 33 be reduced when it is not in operation, allowing personnel, equipment, ore, etc. to pass smoothly in the roadway 33, but also when the inflatable airbag 10 is deployed, the inflatable airbag 10 can fit against the sidewall of the same side of the airbag positioning cavity 32 and the airbag storage cavity 31 to close the opening, which helps to improve the tightness of the sealing.

[0027] Specifically, taking a tunnel 33 with a width of 5m and a height of 2.9m as an example, an airbag placement cavity 32 and an airbag storage cavity 31 with a width of 0.8m can be excavated on the side wall of the tunnel 33. The sealing unit in this embodiment can be applied to tunnels 33 with a width of 2m to 5m and a height of 2m to 3.5m, so the width of the airbag placement cavity 32 and the airbag storage cavity 31 can be adaptively adjusted according to the width of the tunnel 33.

[0028] Furthermore, since airbag positioning chamber 32 and airbag storage chamber 31 are provided on opposite sidewalls of the roadway 33, not only can the side of the inflated airbag 10 facing the working face abut against the U-shaped opening formed by the cross-section of the roadway 33, allowing the inflated airbag 10 and the fireproof cloth to contact the edge of the opening to seal it; but also, on the other side of the airbag positioning chamber 32 and airbag storage chamber 31, i.e. the side of the inflated airbag 10 away from the working face, the other side of the airbag positioning chamber 32 and airbag storage chamber 31 can be used to support the inflated airbag 10. That is, when one side of the inflated airbag 10 presses the fireproof cloth against the aforementioned opening edge, its back side will also adhere to the opening edge of the other side of the airbag positioning chamber 32 and airbag storage chamber 31, thereby achieving sealing using both the front and back sides of the inflated airbag 10.

[0029] like Figure 1 and Figure 2 As shown, optionally, the roadway fire containment device also includes an airbag traction mechanism, which is located at the top of the roadway fire containment device, and the inflatable airbag 10 is driven to the power output end of the airbag traction mechanism.

[0030] By installing an airbag traction mechanism in the airbag positioning cavity 32, the inflatable airbag 10 can be pulled into the airbag positioning cavity 32. Then, by inflating the airbag 10, its thickness increases, thereby fitting against the opening of the tunnel 33 to seal the airbag. The traction of the airbag traction mechanism helps to quickly expand the dimensions of the inflatable airbag 10 in the length direction perpendicular to the tunnel 33 and precisely control the position of the other side of the inflatable airbag 10 to ensure rapid and efficient sealing.

[0031] like Figure 1 and Figure 2 As shown, optionally, the airbag traction mechanism includes a winding assembly 41 and a traction rope. The winding assembly 41 is disposed in the airbag positioning cavity 32, and one end of the traction rope is connected to the winding assembly 41, and the traction rope is configured to be wound around the winding assembly 41.

[0032] By using the winding assembly 41 to wind the traction rope to pull the inflatable airbag 10, a faster operating speed can be achieved, and the inertia of the transmission part is small, which helps to quickly cover the opening of the tunnel 33 with the inflatable airbag 10.

[0033] Specifically, the winding assembly 41 may include a drum to which one end of a traction rope is connected, and the other end of the traction rope is connected to a corner of the inflatable airbag 10. The longitudinal side of the corner can be pulled into the airbag positioning cavity 32. When the drum begins to wind the traction rope, it can move the corner into the airbag positioning cavity 32, thereby causing the inflatable airbag 10 to unfold. The top of the inflatable airbag 10 can be slidably disposed in a slide rail 51 via a slider, and the slide rail 51 is mounted on the top of the bracket 50 described later.

[0034] In this embodiment, the time from the fire being triggered to the completion of the initial sealing is 1 to 2 minutes. Therefore, the time for the winding assembly 41 to pull the inflatable airbag 10 to unfold via the traction rope is 0.5 to 1 minute.

[0035] like Figure 1 and Figure 2 As shown, optionally, the roadway fire sealing device also includes a bracket 50, which is detachably connected to the top of the roadway 33 and the airbag storage chamber 31 and the airbag positioning chamber 32, and the top of the inflatable airbag 10 is slidably connected to the bracket 50.

[0036] By setting up the support 50, a foundation can be formed for the top of the inflatable airbag 10 to slide, which facilitates the rapid deployment of the inflatable airbag 10 in the width direction of the roadway 33. Moreover, the support 50 is detachably connected to the top of the roadway 33, and when the working face position changes, the support 50 and the sealing unit can be disassembled and replaced to a new position, thereby reducing mining costs.

[0037] Among them, the bracket 50 can be made of aluminum alloy, and the load-bearing capacity of aluminum alloy exceeds 50kg.

[0038] like Figure 1 and Figure 2 As shown, optionally, the roadway fire sealing device further includes a first airbag sensor 61 and a second airbag sensor 62. The first airbag sensor 61 and the second airbag sensor 62 are electrically connected to the controller 81. The first airbag sensor 61 is disposed in the airbag storage cavity 31, and the second airbag sensor 62 is disposed in the airbag positioning cavity 32. The first airbag sensor 61 and the second airbag sensor 62 are configured to both detect the inflatable airbag 10 and then send a signal to the controller 81 to control the inflation module connected to the inflatable airbag 10 to inflate the inflatable airbag 10.

[0039] By setting the first airbag sensor 61 and the second airbag sensor 62 in this way, the inflation of the airbag 10 can be started after both the first airbag sensor 61 and the second airbag sensor 62 detect the inflatable airbag 10, so that the inflatable airbag 10 can expand rapidly to close the tunnel 33, thus improving the efficiency of the operation.

[0040] Specifically, the first airbag sensor 61 is located at the top of the airbag storage cavity 31, and the second airbag sensor 62 is located at the top of the airbag positioning cavity 32. The first airbag sensor 61 and the second airbag sensor 62 can be reflective sensors, such as reflective infrared sensors and reflective photoelectric sensors. If the inflatable airbag 10 is located below or directly opposite the first airbag sensor 61 and the second airbag sensor 62, the reflective sensor can send a signal to the controller 81. The presence of the first airbag sensor 61 in the airbag storage cavity 31 ensures that even after the inflatable airbag 10 is deployed by the airbag traction mechanism, one edge remains within the airbag storage cavity 31. This prevents the inflatable airbag 10 from being completely pulled out of the airbag storage cavity 31 before inflation, thus improving the reliability of the operation.

[0041] like Figure 1 and Figure 2 As shown, optionally, the dry powder spraying assembly 20 includes a dry powder spraying nozzle 21, which is configured to spray dry powder toward the edge region of the deployed inflatable airbag 10.

[0042] This setup allows the fireproof layer formed by dry powder spraying to partially seal the gap between the fireproof cloth and the tunnel 33, making the seal more airtight.

[0043] Specifically, in this embodiment, taking the aforementioned length as an example, each dry powder spraying assembly 20 contains at least 5 kg of dry powder extinguishing agent, and the spraying distance is greater than or equal to 3 m. A 10 cm to 15 cm thick fireproof dry powder layer can be sprayed onto the fireproof cloth and / or the inflatable airbag 10 to enhance airtightness.

[0044] like Figure 1 and Figure 2 As shown, optionally, the sealing unit includes two inflatable airbags 10 spaced apart along the length of the tunnel 33; each sealing unit includes four sets of dry powder injection assemblies 20, and the opposite sides of each inflatable airbag 10 are configured to be sprayed by the dry powder injection assembly 20.

[0045] This configuration allows for spraying on both opposite sides of the inflatable airbag 10, thereby improving the sealing performance.

[0046] Specifically, in each sealing unit, two inflatable airbags 10 can be arranged at a 3m interval, and a dry powder spraying assembly 20 is provided on both the side facing the working surface and the side facing away from the working surface of each inflatable airbag 10. That is, in the space between the two inflatable airbags 10, the dry powder spraying assembly 20 sprays towards the side wall of the space.

[0047] The dry powder spraying assembly 20 can be installed at the top of the tunnel 33, facing the top of the deployed inflatable airbag 10. The two sets of dry powder spraying assemblies 20 spray each side of the inflatable airbag 10, respectively, into the airbag storage cavity 31 and the airbag positioning cavity 32 to cover the edge of the inflatable airbag 10.

[0048] like Figure 1 and Figure 2 As shown, optionally, the dry powder spraying assembly 20 also includes a dry powder detection sensor 22, which is used to detect the thickness of the dry powder sprayed onto the inflatable airbag 10.

[0049] By detecting the thickness of the dry powder sprayed onto the inflatable airbag 10, it can be determined whether the spraying process is complete. A lower powder thickness indicates that less dry powder was sprayed, providing information to the control system.

[0050] The dry powder detection sensor 22 is located between two dry powder spraying assemblies 20 on the same side facing the inflatable airbag 10.

[0051] like Figure 1 and Figure 2 As shown, optionally, the roadway fire sealing device also includes a working face temperature sensor 71 and a gas sensor 72, which are configured to be installed in the roadway 33 and spaced 5m to 8m apart from the sealing unit.

[0052] With this setup, the temperature and gas concentration in the tunnel 33 can be automatically detected. When the temperature or gas concentration exceeds the standard, it can be assumed that a fire has occurred in the tunnel 33, thereby providing a signal to the controller 81. This allows the controller 81 to control the sealing unit to take corresponding actions, which can significantly improve the efficiency of the operation.

[0053] Specifically, the detection threshold of the working face temperature sensor 71 in tunnel 33 can be set to 80℃, while the concentration threshold of the gas sensor 72 can be set to a carbon monoxide concentration of 50ppm. That is, when the temperature in tunnel 33 is ≥80℃, the working face temperature sensor 71 provides corresponding information to the controller 81; when the carbon monoxide concentration is ≥50ppm, the gas sensor 72 provides corresponding information to the controller 81. As long as either exceeds the threshold, the controller 81 automatically activates the sealing unit, the inflatable airbag 10 is pulled and deployed by the airbag traction mechanism, and an alarm message is sent to the ground monitoring platform 82. Until both the first airbag sensor 61 and the second airbag sensor 62 detect the inflatable airbag 10, it means that both sides of the inflatable airbag 10 are in their respective positions. Then, the inflation module is activated to inflate the airbag 10. The airbag 10 expands rapidly to compress the fireproof cloth and fit it into the tunnel 33. At the same time, the dry powder injection component 20 sprays dry powder onto the edge of the closed area, thus forming a triple sealed structure of "airbag 10 + fireproof cloth + dry powder" to quickly cut off the oxygen supply to the fire area.

[0054] In summary, this tunnel fire sealing device can achieve the following effects: 1. Fast sealing speed: From fire triggering to initial sealing completion, it only takes one or two minutes, which is ten to dozens of times faster than traditional manual methods; 2. Excellent sealing tightness: The inflatable airbag 10 can adapt to the irregular surface of the tunnel sidewalls, minimizing gaps and achieving an air leakage rate of less than 0.5m. 3 / min, and together with fireproof cloth and dry powder to form a triple sealing effect, completely blocking the oxygen supply; 3. High safety, no personnel need to enter the fire area, and various sensors and controllers 81 are remotely linked to reduce personnel casualties; 4. Wide adaptability, different sizes of supports 50 can be selected according to the cross-sectional dimensions of the roadway 33, within the range of width 2m~5m and height 2m~3.5m, to adapt to different roadway retention scenarios in coal mining faces.

[0055] While this application discloses the above information, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application shall be determined by the scope defined in the claims.

[0056] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] In the above embodiments, descriptions of directions such as "up" and "down" are based on the accompanying drawings.

[0058] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application.

[0059] Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tunnel fire sealing device, characterized in that, It includes multiple sealing units, which are arranged at intervals along the length of the roadway (33); each sealing unit includes a dry powder injection assembly (20) and an inflatable airbag (10) that can be deployed along the width of the roadway (33), the surface of the inflatable airbag (10) being covered with a fireproof cloth, which is arranged on the side of the inflatable airbag (10) facing the working face.

2. The tunnel fire sealing device according to claim 1, characterized in that, It also includes an airbag storage cavity (31) and an airbag positioning cavity (32) disposed in the tunnel (33). The airbag storage cavity (31) and the airbag positioning cavity (32) are located on opposite sidewalls of the tunnel (33). When the inflatable airbag (10) is in a contracted state, it is located in the airbag storage cavity (31). When the inflatable airbag (10) is fully deployed, one side of the inflatable airbag (10) is located in the airbag storage cavity (31), and the other side is located in the airbag positioning cavity (32). The inflatable airbag (10) is configured to drive the fireproof cloth to adhere to the sidewalls of the same side of the airbag positioning cavity (32) and the airbag storage cavity (31).

3. The tunnel fire sealing device according to claim 2, characterized in that, The roadway fire sealing device also includes an airbag traction mechanism, which is located at the top of the roadway fire sealing device. The inflatable airbag (10) is connected to the power output end of the airbag traction mechanism.

4. The tunnel fire sealing device according to claim 3, characterized in that, The airbag traction mechanism includes a winding assembly (41) and a traction rope. The winding assembly (41) is disposed in the airbag positioning cavity (32). One end of the traction rope is connected to the winding assembly (41), and the traction rope is configured to be wound around the winding assembly (41).

5. The tunnel fire sealing device according to claim 3, characterized in that, The roadway fire sealing device also includes a bracket (50), which is detachably connected to the top of the roadway (33), the airbag storage chamber (31), and the airbag positioning chamber (32), and the top of the inflatable airbag (10) is slidably connected to the bracket (50).

6. The tunnel fire sealing device according to claim 2, characterized in that, The roadway fire sealing device further includes a first airbag sensor (61) and a second airbag sensor (62). The first airbag sensor (61) and the second airbag sensor (62) are electrically connected to the controller (81). The first airbag sensor (61) is disposed in the airbag storage cavity (31), and the second airbag sensor (62) is disposed in the airbag positioning cavity (32). The first airbag sensor (61) and the second airbag sensor (62) are configured to both detect the inflatable airbag (10) and then send a signal to the controller (81) to control the inflation module connected to the inflatable airbag (10) to inflate the inflatable airbag (10).

7. The tunnel fire sealing device according to claim 2, characterized in that, The dry powder spraying assembly (20) includes a dry powder spraying nozzle (21) configured to spray dry powder toward the edge region of the deployed inflatable airbag (10).

8. The tunnel fire sealing device according to claim 7, characterized in that, The sealing unit includes two inflatable airbags (10) spaced apart along the length of the tunnel (33); each sealing unit includes four sets of dry powder injection assemblies (20), and the opposite sides of each inflatable airbag (10) are configured to be sprayed by the dry powder injection assembly (20).

9. The tunnel fire sealing device according to claim 7, characterized in that, The dry powder spraying assembly (20) also includes a dry powder detection sensor (22), which is used to detect the thickness of the dry powder sprayed onto the inflatable airbag (10).

10. The roadway fire sealing device according to any one of claims 1-6, characterized in that, The roadway fire sealing device also includes a working face temperature sensor (71) and a gas sensor (72), which are configured to be installed in the roadway (33) and spaced 5m to 8m apart from the sealing unit.

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