EP4379213A1

EP4379213A1 - Forced ventilation device, particularly for road tunnels and the like

Info

Publication number: EP4379213A1
Application number: EP23212520.3A
Authority: EP
Inventors: Mario Bruno LANCIANO; Antonio FERNANDEZ ESCANDON ORTIZ; Corrado Franco MAVERI
Original assignee: Italoiberica Engineering Group SL
Current assignee: Italoiberica Engineering Group SL
Priority date: 2022-12-02
Filing date: 2023-11-28
Publication date: 2024-06-05

Abstract

A forced ventilation device (1), particularly for road tunnels and the like, comprising an outer casing (2) which has a substantially cylindrical hollow geometric shape, is open at its end faces and can be fixed to the walls of a tunnel and the like by means of a supporting frame (3) in such a manner as to be oriented with its axis of revolution (4) parallel to the longitudinal extension of the tunnel and the like; the device further comprises a drive unit (5) provided with a ventilation impeller (6), arranged inside the outer casing (2) by means of supporting brackets (7) radially protruding therefrom in such a way that the axis of rotation (8) of the ventilation impeller (6) coincides with the axis of revolution (4) of the outer casing (2); the drive unit (5) comprises an outer shell (10) adapted to contain the electromechanical components of the drive unit (5) and having an aerodynamic profile that is such as to facilitate the ventilation of air through the outer casing (2).

Description

The present invention relates to a forced ventilation device, particularly for road tunnels and the like.
The main regulations and directives at national and European level on safety in road tunnels and motorway tunnels of length greater than one kilometer require the installation of ventilation systems, individual or centralized, based on the results of risk analysis.
The structural and traffic parameters influencing the choice of type and the dimensioning of the ventilation system are:

length of the tunnel,
area of the transverse cross-section,
vertical alignment of the tunnel,
equivalent traffic volume,
frequency of traffic congestion at full operation
and
weather/climate conditions on site.

The choice and the dimensioning of the ventilation system must take into consideration the statistics for possible accidents that can cause fires and spills of toxic, harmful and inflammable substances.
In addition, they must contribute to ensuring the level of safety set by the application of the risk analysis methodology and they must result in the definition of optimal plant engineering that is capable of ensuring:

the dilution of vehicle emissions inside the tunnel under operating conditions (sanitary ventilation);
the environmental compatibility of the structure; and
the management and control of smoke in the event of possible accidents identified as major (emergency ventilation).

In more detail, sanitary ventilation is designed to dilute the pollutants emitted by motor vehicles under any traffic conditions, and to dilute the pollutants emitted by motor vehicles in the event of the traffic stopping owing to a non-significant accident.
Furthermore, the ventilation has to maintain the concentration of the pollutants inside the structure to levels that are such as not to compromise visibility, and to contain the dose of pollutants inhaled by people.
In parallel, emergency ventilation is designed to disperse the heat energy generated by fire, to manage and control the motion of fumes, and to dilute toxic and inflammable substances.
The ventilation must therefore ensure the safe exit of the people and facilitate the operations of first responders and operations to extinguish fire, as well as prevent the formation of explosive mixtures in the event of a spill.
As mentioned previously, for the scenarios described above, a mechanical ventilation system must be installed in all tunnels longer than one kilometer.
Verification of the need to install a mechanical ventilation system must be extended to include tunnels shorter than one kilometer, when the structural and traffic parameters influencing the safety of the tunnel system are anomalous.
Typically, the choice of recommended ventilation systems for bidirectional road tunnels depends on the length of the tunnels and, in particular, a forced ventilation is chosen for tunnels shorter than or equal to one kilometer, a longitudinal ventilation with a single machine and fume extraction is chosen for tunnels longer than or equal to three kilometers, and a semi-transverse or transverse ventilation is chosen for tunnels longer than or equal to one kilometer and shorter than three kilometers.
For tunnels longer than one and a half kilometers, a probabilistic risk analysis methodology needs to be applied on a case-by-case-basis in order to further evaluate the adoption of a longitudinal-type system supplemented by suitable compensation measures in place of installing a transverse, semi-transverse, or hybrid ventilation system.
The ventilation system must preserve the stratification of fumes generated by a fire event representing the critical events possible in a road tunnel, for a time sufficient to ensure the evacuation of people toward the first available emergency exit.
The ventilation system must be capable of reversing the direction of the air flow at any position of the tunnel within a time compatible with the dynamics of the fire event and the whether the people can be rescued.
According to the aim of correctly managing any event under ordinary circumstances or in an emergency, each fan must be fitted with a speed variator, incorporated directly or in the immediate vicinity.
The system must be capable of ensuring continuity of service at 400°C for at least 90 minutes. Adopting this configuration entails the following advantages:

management of energy consumption as a function of the effective requirements;
elimination of starting peaks; - compensation of power factor;
use of non-screened cables;
reduction to the minimum of emissions of noise toward the network;
smaller cross-sections of cables;
considerable reduction of installed power;
reduction of energy consumption;
substantial reduction of installation and running costs; and
inversion of direction of rotation in a few seconds.

The aim of the present invention consists in providing a forced ventilation device, particularly for tunnels and the like, that meets all the requirements listed above.
Within this aim, an object of the present invention consists in providing a forced ventilation device that is capable of rapidly dissipating the heat brought by any combustion fumes in such a manner as to ensure its correct operation.
Another object of the present invention consists in providing a ventilation device that ensures the highest guarantees of reliability, operation and efficiency.
Last but not least, an object of the present invention is to provide a ventilation device provided using technologies that are per se known, such as to make it economically competitive.
This aim and these and other objects which will become better apparent hereinafter are achieved by a forced ventilation device, particularly for road tunnels and the like, comprising an outer casing which has a substantially cylindrical hollow geometric shape, is open at its end faces and can be fixed to the walls of a tunnel and the like by means of a supporting frame in such a manner as to be oriented with its axis of revolution parallel to the longitudinal extension of said tunnel and the like; the device further comprises a drive unit provided with a ventilation impeller, arranged inside said outer casing by means of supporting brackets which protrude radially from said drive unit in such a way that the axis of rotation of said ventilation impeller coincides with said axis of revolution of said outer casing; characterized in that said drive unit comprises an outer shell adapted to contain the electromechanical components of said drive unit and having an aerodynamic profile that is such as to facilitate the ventilation of air through said outer casing.
Further characteristics and advantages of the invention will become more apparent from the detailed description of a preferred, but not exclusive, embodiment of a forced ventilation device, particularly for road tunnels and the like, illustrated by way of non-limiting example with the aid of the accompanying drawings wherein:

Figure 1 is a perspective view of the forced ventilation device according to the present invention;
Figure 2 is a first perspective view, from the front, of the portion of outer casing containing the drive unit fitted with an impeller of the forced ventilation device shown in Figure 1;

Figure 3 is a second perspective view, from behind, of the portion of outer casing shown in Figure 2;
Figure 4 is a perspective view of the drive unit fitted with an impeller of the forced ventilation device shown in the previous figures.

With reference to the figures, the forced ventilation device, particularly for road tunnels and the like, according to the invention, generally designated by the reference numeral 1, comprises an outer casing 2 which has a substantially cylindrical hollow geometric shape, is open at its end faces and can be fixed to the walls of a tunnel and the like by means of a supporting frame 3 in such a manner as to be oriented with its axis of revolution 4 parallel to the longitudinal extension of the tunnel and the like.
To complete the ventilation device 1, a drive unit 5 is further provided that has a ventilation impeller 6, arranged inside the outer casing 2 by means of supporting brackets 7 radially protruding from the drive unit 5 in such a way that the axis of rotation 8 of the ventilation impeller 6 coincides with the axis of revolution of the outer casing 2.
In more detail, the outer casing 2 comprises a central portion 2a, directly associated with the drive unit 5 and directly associable with the walls of the tunnel and the like, and two end portions 2b and 2c associated with the central portion 2a by means of a bolted flanged profile 9 and respectively adapted to convey and expel the ventilated air from the drive unit 5.
According to the invention, the drive unit 5 comprises an outer shell 10, adapted to contain the electromechanical components of the drive unit 5 and having an aerodynamic profile that is such as to facilitate the ventilation of air through the outer casing 2. The outer shell 10 is smooth, without cooling fins.
In more detail, such outer shell 10 comprises a cylindrical jacket 10a provided with a closure dome 10b arranged on the opposite side with respect to that of the ventilation impeller 6.
Conveniently, both the outer shell 10 and the ventilation impeller 6 are made of stainless steel so as to offer an effective resistance to the corrosive action of the fumes present in the ventilated air.
In this way, the ventilation impeller 6, using the rotation of the driving shaft, moves the air around the outer shell 10 of the motor, in so doing enabling a cooling action.
Advantageously, the drive unit 5 is associated with a control unit 11, situated outside the outer casing 2, by means of electrical wiring accommodated in a tubular body 12 interposed between the drive unit 5 and the outer casing 2, extending radially with respect to the drive unit 5.
According to this embodiment, the drive unit 5 comprises an electric motor of the three-phase asynchronous type, constituted by a stator provided by a plurality of mutually insulated laminations having a thickness of preferably 0.5 millimeters, and by a rotor constituted by a cast cage made of aluminum alloy or copper alloy.
Conveniently, the forced ventilation device 1 can be inserted into a forced ventilation system that comprises a plurality of forced ventilation devices 1 installed in a road tunnel or the like, or in a network of road tunnels or the like.
The operation of the forced ventilation device 1 is the following.
Under normal conditions, assuming a ventilation system configuration that comprises multiple forced ventilation devices 1, each forced ventilation device 1 located inside the tunnel can start in a coordinated manner with the other forced ventilation devices 1, at reduced speed if they are powered by speed variators, in order to eliminate the gases under normal conditions of transit or when vehicles are stopped owing to an accident that does not result in fire.
Conveniently, all the forced ventilation devices 1 adjust their speeds in rpm and in the most suitable direction of flow, based on the environmental conditions.
Differently, if the system is powered directly, only the quantity of forced ventilation devices 1 required for sanitary ventilation is activated.
In case of fire and with the forced ventilation devices 1 in operation, these will be regulated as a function of the location and characteristics of the fire.
The devices located at the point where the fire is located will operate under normal conditions up to a temperature of 60° C, after which, by means of a command imparted by the thermostat of the inverter in the control unit 11, the switchover to direct operation will be effected, operating under these conditions up to 400°C for a maximum length of time of two hours.
Differently, in the event of a fire but with the forced ventilation devices 1 stopped, the forced ventilation devices 1 that are located outside the zone of the fire are started by variator, the forced ventilation devices 1 that are located in the zone of the fire and/or with a temperature higher than 60° C are started directly, as they can operate under these conditions at up to 400°C for two hours.
Also in these two scenarios, if the forced ventilation devices 1 are powered directly, pairs of devices will be started in sequence, so as to avoid exceeding the capacity of the network.
The forced ventilation devices 1 can furthermore be controlled by a control unit which, by means of programs that receive information from pressure sensors, temperature sensors, environmental pollution sensors, etc. located inside the tunnel and connected via a bus connection provided by fire-resistant cables or optic fibers, analyzes all the parameters and sets the speed and correct directions for operation under optimal conditions from the point of view of safety and energy consumption.
In practice it has been found that the forced ventilation device, particularly for tunnels and the like, according to the present invention achieves the intended aim and objects in that the electric motor is made completely of sheet steel, smooth, without cooling fins and/or with reinforcement and fixing components, with an aerodynamic shape and unpainted.
Furthermore, one of the main advantages of the forced ventilatio device according to the present invention consists of the possibility of providing ventilation systems with different power levels, while keeping the same diameter and increasing the thickness of the stator and rotor pack, therefore only increasing, as a function of the power required, the length of the motor.
This particular fact entails an increase in fluid dynamic efficiency as power increases, and the simplification of production and storage of the stator and rotor pack, since sheet steel with the same characteristics and diameter is always used for the different power levels.
In particular, it is possible to highlight the following advantages with respect to known ventilation devices:

reduction of absorbed power;
substantial reduction of rated current;
considerable reduction of noise levels;
permanent control of air flow;
reduction of vibrations;
considerable reduction in weight;
reduction of energy consumption;
excellent fluid dynamic behavior;
high resistance to the fatigue deriving from the continuous change of speed and of the direction of rotation; and
considerable increase of useful life;
ease of maintenance.

The forced ventilation device thus conceived is susceptible of numerous modifications and variations all of which are within the scope of the appended claims.
Moreover, all the details may be substituted by other, technically equivalent elements.
In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements and to the state of the art.
The disclosures in Italian Patent Application No. 102022000024888 from which this application claims priority are incorporated herein by reference.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A forced ventilation device (1), particularly for road tunnels and the like, comprising an outer casing (2) which has a substantially cylindrical hollow geometric shape, is open at its end faces and can be fixed to the walls of a tunnel and the like by means of a supporting frame (3) in such a manner as to be oriented with its axis of revolution (4) parallel to the longitudinal extension of said tunnel and the like; the device further comprises a drive unit (5) provided with a ventilation impeller (6), arranged inside said outer casing (2) by means of supporting brackets (7) which protrude radially from said drive unit (5) in such a way that the axis of rotation (8) of said ventilation impeller (6) coincides with said axis of revolution (4) of said outer casing (2); characterized in that said drive unit (5) comprises an outer shell (10) adapted to contain the electromechanical components of said drive unit (5) and having an aerodynamic profile that is such as to facilitate the ventilation of air through said outer casing (2).
The forced ventilation device (1) according to claim 1, characterized in that said outer shell (10) comprises a cylindrical jacket (10a) having a circular base provided with a closure dome (10b) arranged on the opposite side with respect to said ventilation impeller (6).
The forced ventilation device (1) according to claim 1 or 2, characterized in that said ventilation impeller (6) is made of stainless steel.
The forced ventilation device (1) according to one or more of the preceding claims, characterized in that said outer shell (10) is made of stainless steel.
The forced ventilation device (1) according to one or more of the preceding claims, characterized in that said drive unit (5) is associated with a control unit (11) arranged externally to said outer casing (2).
The forced ventilation device (1) according to claim 5, characterized in that said control unit (11) is functionally connected to said drive unit (5) by means of electrical wiring accommodated in a tubular body (12) interposed between said drive unit (5) and said outer casing (2), extending radially with respect to said drive unit (5).
The forced ventilation device (1) according to one or more of the preceding claims, characterized in that said outer casing (2) comprises a central portion (2a), directly associated with said drive unit (5) and directly associable with the walls of a tunnel and the like, and two end portions (2b, 2c) which are respectively adapted to convey and expel the ventilated air from said drive unit (5).
The forced ventilation device (1) according to one or more of the preceding claims, characterized in that said drive unit (5) comprises an electric motor of the three-phase asynchronous type.
The forced ventilation device (1) according to one or more of the preceding claims, characterized in that said electric motor comprises a stator provided by a plurality of mutually insulated laminations having a thickness of preferably 0.5 millimeters.
The forced ventilation device (1) according to one or more of the preceding claims, characterized in that said electric motor comprises a rotor constituted by a cast cage made of aluminum or copper alloy.
A forced ventilation system, characterized in that it comprises a plurality of forced ventilation devices (1) according to one or more of the preceding claims, which are adapted to be installed in a road tunnel or the like or in a network of road tunnels or the like.