This invention refers to a filtration system for rail air-conditioning facilities, intended to achieve optimum ventilation of the passenger compartment of the train in combination with a set of air-conditioning facilities.

The purpose of the invention is to reduce the space necessary for the assembly of the filtration means used and the air-conditioning facilities associated with them.

In the air conditioning of trains and specifically in those trains envisaged to travel along desert areas in which sand storms are frequent, it is necessary to have filtration means to prevent the passage of sand, all this in combination with air-conditioning facilities prepared for these purposes.

Well at present, the relationship between the air-conditioning facilities and the filtration means is carried out at a distance, that is to say, via ducts and means representing a very notable volume occupation, independently from whether the filtration system includes a single inlet for clean from outside, which on occasions is far from ideal as the wind direction, together with the travel direction of the train, may coincide or not, and in those cases in which the train travels in the opposite direction to the wind direction, it is inevitable sand will get in, even obstructing the inlet and the actual filtration means used.

The filtration system proposed was conceived to solve the problem stated above, based on a new idea for the implementation of the actual filtration system in combination with the air-conditioning facilities.

To be more precise, the filtration system is based on the fact that the filtration means are connected directly to the air-conditioning facilities, therefore minimising the distance between the aforementioned filtration means and the actual air-conditioning facilities, which reduces pressure head losses and makes it possible to use the smallest possible fan motors, for the set to occupy a space which is minimal.

On the other hand, the filtration means used are made up by a common duct for two inlets located in opposite directions, allowing for clean external air to be sucked in by one inlet or the other, depending on the direction the train is travelling in and the actual direction of the prevailing wind.

Also, in combination with these filtration means, means have been envisaged to automatically select the opening of the inlet chosen to suck in clean external air, depending on the prevailing wind and the direction the train is travelling in, as already commented.

In this way and by virtue of the fact the air input through one or the other side can be managed, performance will always be optimal and most advantageous, it also being possible to establish for both inlets to close in conflictive sand areas and for the corresponding inlet to open in cleaner areas.

Each of the filtration means includes a nozzle with a filtration grille, a trapezoidal nozzle and with both inlets being positioned opposite to each other, for their less wide ends to concur at the common duct with a constant cross-section.

It is also envisaged that the common duct for both inlets lead to a common chamber, in which cyclonic filters are provided, where the sand that may have entered with the clean air will be withheld, with this sand then being extracted by means of an extractor motor established in accordance with that cyclonic filter chamber.

Another new characteristic is that previously to the common chamber there may be a single door or a door for each of the sections corresponding to one or the other air suction inlet.

Finally, it should be stated that all the parts and components referred to, that is to say, chambers, ducts, air-conditioning facilities, etc., will be closed by means of their corresponding opening doors to enable the maintenance and cleaning of the entire filtration system as far as possible.

Based on the aforementioned characteristics and apart from the advantages already stated, a sandstorm-proof system is established, avoiding the filters from collapsing in the case of a sand storm occurring.

The space occupied by the filtration means and the other components is minimal, thus notably saving space in the corresponding roof in which the set of the filtration system and the air-conditioning facilities is to be implemented.

Another characteristic is that the sand extractor motor remains fully protected from the air while the train is in motion, due to the symmetrical layout of the expansions determined by the air inlets.

In order to supplement the description below and so as to help understand the characteristics of the invention better, in accordance with a preferential example of its practical execution, a series of illustrative but not exhaustive pictures are included as an integral part of such description, representing the following:

• Figure 1.- This shows a representation corresponding to a view from above of the filtration system which is the aim of the invention, without the corresponding covers, allowing for all the components and their locations to be seen.
• Figure 2.- This shows the same set represented in the previous figure only with the covers this time, closing all the compartments corresponding to the filtration means, while leaving open an uncovered the location for the air conditioning.

As may be seen in the figures referred to above, the filtration system for rail air-conditioning facilities executed in accordance with the purpose of the invention, is envisaged to be associated with air-conditioning facilities (1) and achieving air conditioning of the train, presenting as its first peculiarity the fact that such air-conditioning facilities are connected directly to the filtration means of the system with these being made up by a duct (2) which at its ends is finished off by two symmetrical expansions (3) in a trapezoidal shape, in such a way that each of them is provided with a nozzle (4) for air input, with a grille (5) to filter this air, in such a manner that the air accesses the common duct (2) thorough the expansions (3), and, via the corresponding doors (6), one for each section of the duct (2), it can reach the entrance (7) to a common chamber (8) provided with cyclonic filters to withhold the sand that may have entered with the clean external air as this was sucked by the actual filtration system.

The doors (2) may be in the form of a single door located at the entrance (7) of the common chamber (8).

The sand reaching the common chamber (8) is sucked by an extractor motor (9) which is perfectly protected against the wind and the sand where the ends of the common duct finish off (2).

The filtration system also includes filter mesh (10).

Both the duct (2) with its expansions (3) and the common chamber (8) of the cyclonic filters and the area for the location of the filter mesh (10), are supplemented with their corresponding opening covers (11), the same as the area of the air-conditioning facilities (1), in order to allow for these covers to be opened (11) to perform the maintenance and cleaning of all the components.

The nozzles (4) established at the opposing air inlets to the filtration system, present and inclination established in the grilles themselves (5) of such inlet nozzles (4), establishing a protection for these grilles (5) which makes the air either fall, due to its own weight before entering the grilles, or aerodynamically flow over them.

The air filtered through the common chamber (8) by the cyclonic filters, goes on to the filtration mesh (10), that is special and which collects the rest of the sand, to only allow through it clean air for the air-conditioning facilities (1).