EP2964830B1

EP2964830B1 - Suction system for flammable or polluting liquids

Info

Publication number: EP2964830B1
Application number: EP14723503.0A
Authority: EP
Inventors: Gianluca Della Valle; Alessandro Pini; Mario Vitarelli
Original assignee: Autostrade per LItalia SpA
Current assignee: Autostrade per LItalia SpA
Priority date: 2013-03-06
Filing date: 2014-02-26
Publication date: 2017-03-22
Anticipated expiration: 2034-02-26
Also published as: PT2964830T; WO2014136132A1; ITFI20130047A1; ES2629388T3; EP2964830A1

Description

The present invention relates to a system adapted to minimize the risks consequent to spillage of flammable or polluting liquids in closed environments such as in particular, but not necessarily, road or railway tunnels, subway or underpass.
The risks connected to the uncontrolled spillage of polluting, toxic and/or flammable substances onto the road surface are well known, said spillage being possible in particular from heavy vehicles, in the case of accidents, but also simply due to defects of sealing of the tanks wherein these substances are contained and transported. Very serious and even tragic consequences have moreover arisen in the past from events of this type.
Collection of these spillages where they occur and possibly before an uncontrolled risk derives therefrom is moreover critical to manage, bearing in mind in particular that it has to be effective, fast and also and above all guarantee safety in the eventuality wherein the idea is that of aspirating the potentially flammable liquids from an environment wherein a fire has already developed. In a circumstance of this kind the suction of air has absolutely to be avoided, whose high temperature (even 400° - 600°C) generates the possibility of combustion or even explosion inside pipes and consequent uncontrolled spread of the fire and of the relative consequences also outside of the original environment.
DE-U-29500454 is regarded as being the prior art closest to the subject-matter of claim 1 and discloses a suction system (fig. 2) for liquid spills in a work environment (tunnel), comprising a number of catch basins distributed over said environment and adapted to collect said spills; sewer means communicating with said basins, provided with implicitly at least one pneumatic inlet and of at least one liquid spill outlet out of said work environment; vacuum generator means adapted to produce a vacuum in said sewer means to suck said liquid spills from said basin.
J The present invention sets out to avoid this state of affairs by providing a suction system for liquid spills inside environments such as road or railway tunnels which is able to provide for a rapid and effective evacuation of the liquids in safe conditions with respect in particular to the need to avoid the risk of spread of the flame in the case of incipient fires or fires already underway.
This result is achieved with a suction system for liquid spills inside environments such as in particular but not necessarily road or railway tunnels, whose basic features are defined in the first of the appended claims.
Further important features are contained in the dependent claims.
The features and the advantages of the suction system for liquid spills inside environments such as in particular not but necessarily road or railway tunnels according to the present invention will be made clearer by the following description of one of its embodiments given by way of a non-limiting example with reference to the accompanying drawings in which:

Figure 1 shows in the form of a circuit diagram the general structural configuration of a system according to the invention;
Figure 2 shows, enlarged, the zone circumscribed by the circle II of Figure 1;
Figure 3 is a plan view from the top of a suction catch basin of the system according to the invention;
Figures 4 and 5 are sections of the catch basin of Figure 3 respectively along the planes denoted by arrows IV-IV and V-V in the same drawing; and
Figures 6a to 6d schematise respective successive moments of a phase of suction of the liquids in a catch basin of the system according to the invention.

Referring for the time being to Figures 1 and 2, a system according to the invention provides a plurality of suction catch basins 1 distributed regularly inside the work environment (i.e. the one wherefrom the liquids are to be aspirated). In the case of a road tunnel (block G shown in Figure 1), the catch basins 1 will be typically distributed in an equidistanced manner along the road, normally along the sides thereof, along a substantially linear layout. A suction suitable for ensuring the required vacuum is made in the catch basins 1 by means of a sewer 2 (which can be simplified as a single conduit yet can be more generically represented as an articulated network) which extends between the catch basins 1, establishing a pneumatic communication with them and between them. Inside the catch basins 1, the specific configuration whereof will be described here below, the liquids collected are then aspirated inside the sewer maintained in a vacuum (as shown by the arrows F1, F2 in Figure 2 which in fact represent respectively the inlet and the suction of the liquid component).
The vacuum/suction is fed into the sewer or network 2 by a vacuum generator 3 (for example a vacuum pump of features in themselves and for themselves known) placed outside the environment G. The sewer or network 2 according to the invention is then configured so as to provide an inlet 4 which draws (aspirates) feed air, along the arrow F3, from an environment E external with respect to the environment G and therefore not affected by the events, for example and in particular the rising of temperature following a fire, underway in the aforesaid environment G. It is clear from the above that as far as the present disclosure is concerned the environment G does not necessarily represent a closed environment, or a completely closed environment, but simply a first work environment separate trough a physical restricting element (such as a wall, a barrier, a portion of soil of suitable extension, a building element, etc.) wherein the first work environment G is subject to spilled liquids that have to be subjected to suction while the second environment is a separate environment not interested by said spilled liquids.
Referring now in particular to Figures 3 to 5, going into detail as to the configuration of a catch basin 1, this provides a more properly defined catch basin 11, which defines a buried compartment 12 wherein due to gravity, through for example an upper closure grating 13, coplanar with the road surface or other types of inlet depending on the specific boundary conditions and design choices during installation, the liquids to be collected fall.
A liquid feed tube 14 extends inside the compartment 12, near the bottom, which, intercepted by a valve 15, connects to the sewer 2. The valve 15 is associated to a control device 16 adapted to open mechanically the same valve when the reaching of a predetermined degree of filling of the compartment 12 of the catch basin by the liquids is detected. For this purpose also the device 16 for controlling the valve 15 dips in the compartment 12 with its own detection tube 17. The height reached by the free end of this tube is correlated to the level of liquid suitable for triggering the control (i.e. the opening) of the valve.
Both the device 16 and the valve 15 are housed in their own case 18 mounted on the sewer 2 and traversed by the latter. The case 18 is hydraulically insulated with respect to the actual catch basin 11, which increases safety and facilitates the operations of maintenance, avoiding risks of contamination for operators.
Returning to the tubes 14, 17 which extend inside the compartment 12 of the actual catch basin 11, according to an important aspect of the invention, the (inlet) end of the feed tube 14 is placed at a significantly lower level with respect to the level of control of the detection tube. This aspect, in its important functional repercussions, is clarified by Figures 6a to 6b, to which specific reference is made here below.
Figure 6a shows a rest situation, wherein the liquids inside the compartment 12 are either absent or have in any case, as specified in the drawing, such a level as not to reach the level of activation determined by the end of the detection tube 17. The valve 15 is therefore closed and, despite the fact the relative feed tube 14 dips into the liquid, there is no suction.
When the level of the liquid (Figure 6b) rises until exceeding the level of activation, the control device 16 commands the opening of the valve 15 with consequent triggering of the action of suction and drawing of the liquid, and only the liquid, towards the sewer 2 (Figure 6c). When the level of the liquid lowers below the threshold of activation (Figure 6d), the device 16 commands the closure of the valve and therefore the interruption of suction. In this phase however the feed tube 14 is still immersed in the liquid, and consequently any suction of air into the sewer 2 is prevented.
It is clear how, if a fire is underway and therefore the air is at a high temperature, the expedient described above avoids the spread of this air in the sewer and towards the exterior to trigger a potential spread of the flame. If this is combined with the fact that, as indicated above, the suction air is drawn from an outside environment, the efficacy of the system according to the invention as regards fire-fighting safety will immediately be clear, without penalising the speed and the efficacy of the extraction which instead will in turn be fully satisfactory, all this with a simple and reliable plant configuration.
Valve 15 and control device 16 have not been described in detail in that their configuration is in itself known, also as regards the mode of reciprocal interaction, which can be drawn for example from the sector of vacuum drains. It should moreover be noted how the functioning of these components is of a purely mechanical-pneumatic nature and therefore without resort to any electrical power supply, with clear advantages in terms of safety, reliability and consumption.
As regards the control device 16 it may for example base its detection and consequent control on the increase in pressure of the air which occurs inside the tube 17 following the rising of the level of the liquids (situation in Figure 6b). With this system differential activation may take place, in the sense that if the vacuum present in the sewer 2 is high, a higher quantity of liquids will be necessary in order to trigger activation, whereas if the vacuum is low, a smaller quantity of liquids will be sufficient. In this way the control device optimises its functioning on the basis of the vacuum instantaneously present in the sewer, with obvious benefits for the entire system of the vacuum, the air/water accrual being maintained always constant.
From the strictly constructional viewpoint, the result may be obtained with a membrane whose deformation responds to the increase in pressure recorded in the tube 17 due to the rising of the level of the liquid and which as a consequence of this deformation actuates a mechanical piston transmission. The latter in turn acts on a switch which, once open, places in pneumatic communication a channel of transmission of the vacuum derived from the sewer 2 to a channel of pneumatic connection to the valve. The consequent transmission of vacuum determines the deformation of a membrane which liberates the opening of the valve, allowing the suction of the liquid by the sewer 2. When the liquid drops below the level of activation in the detection tube 17 there is no longer pressure and the membrane of the control device, due to the gravity, returns into the starting position, closing the above-mentioned pneumatic switch. The vacuum no longer reaches the valve which closes its own membrane assisted by the action of a spring.
Although reference has been made generically to atmospheric air, the suction fluid can in truth be constituted by other aeriform substances such as inert gas. As anticipated, the preferred embodiment of the invention provides for the realisation of a sewer which, starting from an "external" environment E, transits through the environment G wherefrom the liquids have to be aspirated, connecting to the suction catch basins 1 (inhibited from aspirating air), in order to reach finally the vacuum generator 3, so that the atmosphere of the environment E may not interfere with the liquid aspirated in the sewer 2; however, more generically, other systems architectures configured according to the same principle may be realised.
The present invention has been described hitherto with reference to its preferred embodiments. It should be understood that other embodiments may exist which relate to the same inventive sphere, all coming within the scope of protection of the claims given here below.

Claims

A suction system for liquid spills in a work environment (G), the system comprising: a number of catch basins (1) distributed over said environment and adapted to collect said spills; sewer means (2) communicating with said basins (1), provided with at least one pneumatic inlet (4) and of at least one liquid spill outlet out of said work environment; vacuum generator means (3) adapted to produce a vacuum in said sewer means (2) to suck said liquid spills from said basins; wherein said pneumatic inlet is arranged in an environment (E) external to said work environment (G); and wherein each of said basins (1) comprises: valve means (15) for blocking the suction by said sewer means (2); and control means (16) of said valve means (15) as a function of the level of liquid spills in the basin (1), said control means (16) and said valve means (15) being configured so that the blocking position of said valve means (15) is set when the level of liquids in the basin is such to prevent the suction of air by said sewer means (2).
The system according to claim 1, wherein said basin (1) comprises a compartment (12) adapted to collect said spills, said compartment (12) housing a liquid feed tube (14) for feeding the liquid spills to said sewer means (2) and provided with said blocking valve means, and liquid level detection means (17) associated to said control means (16), said detection means (17) being configured such as the level of liquids detected in the compartment (12) that triggers the blocking/unblocking action of said valve means (15) is higher than the level at which the liquid spills enter the feed tube (14).
The system according to claim 2, wherein said detection means comprise a detection tube (17) projecting inside said compartment (12) to a valve activation level higher than the level of liquid intake of said feed tube (14).
The system according to claim 3, wherein said detection tube (17) is adapted to trigger the valve activation control based on an increase or decrease of the air pressure occurring within the same tube further to the raising or lowering of the liquid level in said compartment (12).
The system according to any of the claims 2 to 4, wherein said detection means (17) and said valve means (15) are housed in a case (18) hydraulically isolated with respect to said compartment (12).
The system according to any of the previous claims, wherein said sewer means (2) start from said external environment (E), pass through said work environment (G) being therein connected in sequence to said basins (1) and finally reach said vacuum generating means (3) arranged in proximity with said spil outlet.
The system according to any of the previous claims, wherein said work environment (G) is a road or railway tunnel, subway or underpass.