Patent Description:
The present invention also relates to a method for controlling an aircraft capable of hovering.

In the aviation sector, aeroplanes are normally used for high cruising speeds, in particular greater than <NUM> knots and high altitudes, e.g. above <NUM>,<NUM> feet. At high cruising speeds and altitudes, aeroplanes use fixed wings to generate the lift necessary to sustain the plane itself. A sufficient value of this lift can only be obtained by accelerating the aeroplane on runways of considerable length. These runways are also necessary to allow the same aeroplanes to land.

In contrast, the helicopters normally have lower cruising speeds than those of the aeroplanes and generate the necessary lift for sustenance through the rotation of the blades of the main rotor. As a result, helicopters can land/take off without the need for a horizontal speed and using particularly small surfaces. Moreover, helicopters are able to hover and to fly at relatively low altitudes and speeds, resulting thus as particularly manoeuvrable and suitable for demanding manoeuvres such as rescuing people in the mountains or at sea.

Nevertheless, helicopters have inherent limitations in terms of maximum operating altitude, which is around <NUM> feet, and of maximum operating speed, which cannot exceed <NUM> knots.

In order to meet the demand for aircrafts capable of presenting the same manoeuvrability and comfort of use as the helicopter and at the same time overcoming the inherent limitations mentioned above, convertiplanes and heliplanes are known.

An example of a convertiplane is described in patent application <CIT>.

In greater detail, the convertiplane described in the aforesaid application essentially comprises:.

The rotors are tiltable with respect to the wing around a fourth axis, preferably parallel to the second axis.

The convertiplanes are also able to selectively assume:.

Thanks to the possibility of tilting the rotors, the convertiplanes are able to take off and land like a helicopter, i.e. in a direction substantially perpendicular to the first longitudinal axis of the convertiplane, without the need for a runway.

Furthermore, the convertiplanes are able to take off and land on rough terrains and without generating a noise level incompatible with an urban settlement.

In addition, the convertiplanes are capable of hovering when arranged in the helicopter configuration.

Furthermore, the convertiplanes can reach and maintain cruising speeds of approximately <NUM>-<NUM> knots and flight altitudes of the order of <NUM> feet when arranged in the airplane configuration.

This cruising speed is well above the value of about <NUM> knots that defines the maximum cruising speed of the helicopters.

Similarly, the above altitude is well above the one typical of the helicopters and allows convertiplanes arranged in an airplane configuration to avoid the clouds and atmospheric disturbances characteristic of lower altitudes.

The heliplanes, such as, for example, the EUROCOPTER X-<NUM> aircraft comprise, in addition to the components commonly found in a known helicopter such as a main rotor with vertical axis, a pair of half-wings protruding cantilevered from respective parts of the fuselage of the heliplane along a fourth transverse axis substantially orthogonal to a fifth longitudinal axis of the aircraft and to the axis of rotation of the main rotor.

In more detail, each of the half-wings carries a respective propeller which comprises, in a known manner, a drive shaft operable by a relative motor and a plurality of blades articulated on the drive shaft itself.

In particular, each drive shaft is rotatable around a relative sixth axis substantially parallel to the longitudinal axis of the heliplane, i.e., a horizontal axis.

The heliplane is therefore able, in the same way as the convertiplane, to take off and land in a vertical direction by means of the main rotor and to fly in forward flight by means of the propellers and the aforesaid half-wings.

During the forward flight, the main rotor rotates idly while the thrust is generated by the propellers.

Electrically-propelled or hybrid-propelled aircrafts are known wherein at least one propulsion element (e.g. a propeller or rotor) is operable by battery-powered electric motors.

In such aircrafts, the temperature of the batteries must be strictly maintained within a temperature range. In fact, an uncontrolled increase in the temperature of the batteries could lead to a condition known as "thermal runaway", in which flames are formed or explosions are triggered, and which can have disastrous consequences for the entire aircraft.

In the field of the electrically- or hybrid-propelled aeroplanes, a number of battery cooling solutions have been developed, including those shown in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

According to these solutions, a battery of the aeroplane is arranged inside a cooling duct obtained in the fuselage or at a wing and is impinged by an air flow due to the motion of the aircraft itself.

However, such solutions developed specifically for aeroplanes do not make it possible to effectively regulate the temperature of the batteries of the aircraft capable of hovering.

<CIT> discloses an aircraft nacelle having a first and second heat exchanger section to cool aircraft during different modes. Additionally, a fan and other components are configured to maximize efficiency and cooling capacity during a plurality of operating conditions.

<CIT> discloses a fixed-wing unmanned aerial vehicle air cooling type fuel cell double-stack integrated power system. The system comprises a fuselage, a power motor, a high-pressure hydrogen storage tank, wings, two air cooling type fuel cell stacks symmetrically arranged in the middle of the fuselage or on the wings, and two heat dissipation systems corresponding to the air cooling type fuel cell stacks; an air flow channel of the electric pile is a parallel wave-shaped flow channel; when the galvanic pile is arranged in the middle of the machine body, the cooling system further comprises a cooling fan; when the galvanic pile is arranged on the wings, the power system is suitable for the unmanned aerial vehicle with auxiliary propellers on the wings, and the heat dissipation system further comprises a wing front air guide cover; when the unmanned aerial vehicle is started or flies at a low speed, a medium speed and a high speed, the reaction temperature of the galvanic pile is controlled to be in an ideal temperature interval through different heat dissipation modes.

<CIT> discloses a multi-rotor helicopter having a fuselage and a plurality of fan units. Each of the fan units is equipped with a circular fan frame, a rotating blade, and a drive-system cooling unit. Each drive-system cooling unit has: an accommodation container that accommodates at least one of a drive unit, a driver, and a power source; a cooling fan that supplies cooling air to the accommodation container; an intake flow path that guides air from the cooling fan toward the accommodation container; and an exhaust flow path that discharges air that has passed through the accommodation container. The discharge flow path discharges air that has passed through the accommodation container in the tangent direction of the fan frame.

In aircrafts capable of hovering, in fact, the risk that the temperature of the batteries increases in an uncontrolled way is particularly high, especially while hovering. Specifically, in this flying condition, the air flow rate that invests the aircraft and that would be destined for heat exchange with the batteries is much lower than during the forward flight.

There is a perceived need in the industry to realize an aircraft capable of hovering, wherein the temperature of the batteries can be regulated efficiently.

Aim of the present invention is to realize an aircraft capable of hovering, which allows to meet the need specified above in a simple and economical way.

According to the invention, this aim is achieved by an aircraft capable of hovering as claimed in Claim <NUM> and by a method for controlling an aircraft capable of hovering as claimed in Claim <NUM>.

For a better understanding of the present invention, a preferred non-limiting embodiment is described below, purely by way of example and with the aid of the attached drawings, wherein:.

With reference to <FIG> and <FIG>, <NUM> denotes an aircraft capable of hovering with at least partly electric propulsion.

In greater detail, the aircraft <NUM> is a convertiplane selectively switchable between:.

It must be specified that in the following present disclosure, expressions such as "upper", "lower", "at the front", "at the back" and the like are used with reference to normal forward flight or "hovering" conditions of the aircraft <NUM>.

It is possible to identify a triplet of axes integral to the aircraft <NUM> and originating at a centre of gravity of the aircraft <NUM> itself formed by:.

It is also possible to define a median plane M of the aircraft <NUM> with respect to the axis X and directed parallel to the axis Y.

The aircraft <NUM> essentially comprises:.

In detail, the cooling system <NUM> is adapted to regulate the temperature T of the batteries <NUM> by means of the heat exchange between an air flow taken from the outside and the batteries <NUM>.

The aircraft <NUM> could further comprise one or more thermal motors for driving one or more of the rotors 3a, 3b and <NUM>. In other words, the aircraft <NUM> could be with hybrid propulsion.

As shown in <FIG> and <FIG>, the fuselage <NUM> defines a nose <NUM> and a tail <NUM> of the aircraft <NUM>, which are opposite to each other along the longitudinal axis Y. In addition, the fuselage <NUM> comprises a belly <NUM>, which is interposed between the nose <NUM> and the tail <NUM> along the longitudinal axis Y.

In detail, the belly <NUM> is adapted to be facing towards the ground during the normal operation of the aircraft <NUM>.

With reference to the normal forward flight operating conditions, the aircraft <NUM> proceeds in a direction oriented from the tail <NUM> to the nose <NUM> with a forward speed v with respect to the ground (<FIG>).

In greater detail, the aircraft <NUM> comprises:.

In detail, the axis H is parallel to the axis X.

The axes B, C and the axes D, E lie on two respective planes parallel to the axes X and Z.

In addition, the axes B and C are incident with each other and are tilted with respect to the axis Z, in particular at a point arranged above the belly <NUM>. In greater detail, the axes B and C are both tilted by <NUM>° with respect to the axis Z.

Similarly to the axes B and C, the axes D and E are incident with each other and tilted with respect to the axis Z, in particular at a point arranged above the belly <NUM>. In greater detail, the axes D and E are both tilted by <NUM>° with respect to the axis Z.

The rotors of each pair of rotors 3a and 3b are arranged symmetrically with respect to the median plane M. In addition, the pair of rotors 3a is arranged at the nose <NUM>, the pair of rotors 3b is arranged at the tail <NUM>, and the pair of rotors <NUM> is interposed between the pair of rotors 3a and the pair of rotors 3b along the longitudinal axis Y.

The axes F, G are arranged orthogonally to the axes B, C; D, E and parallel to the axis Y when the rotors <NUM> are arranged in the first position.

The axes F and G are arranged parallel to the axis Z when the rotors <NUM> are arranged in the second position (<FIG>).

Preferably, the rotors 3a, 3b and <NUM> are with fixed pitch.

In the embodiment shown, each of the rotors 3a, 3b and <NUM> is driven by a respective electric motor of the electric drive means. In detail, each electric motor is operable independently of the other electric motors.

The aircraft <NUM> further comprises a control unit <NUM> (only schematically shown in <FIG>) receiving as input a plurality of control signals provided by the crew, by an autopilot or a remote control system, and programmed to provide as output a plurality of commands to command the rotors 3a, 3b and <NUM> so that they provide desired values of the relative thrusts. In greater detail, the control unit <NUM> is programmed to command the rotors 3a, 3b and <NUM> to generate respective thrusts independent of each other.

Referring to <FIG>, the cooling system <NUM> comprises:.

In particular, the batteries <NUM> are placed within the passage <NUM> and are fluidically interposed between the opening <NUM> and at least part of the openings <NUM>.

The cooling system <NUM> comprises two fans <NUM> adapted to increase the kinetic energy of the air contained in the passage <NUM> (<FIG>); these fans <NUM> are adapted to be operated when the forward speed v of the aircraft <NUM> with respect to the ground is lower than a speed threshold value v0 and/or when the temperature T of the batteries <NUM> exceeds a temperature threshold value T0.

For example, the temperature threshold value T0 is lower than <NUM>. Preferably, the temperature threshold value T0 is equal to <NUM>.

The control unit <NUM> is also operatively connected to the fans <NUM> to control their operation, i.e. to command the rotation of the fans <NUM> around respective rotation axes I, J (<FIG>).

In detail, when the forward speed v is greater than the speed threshold value v0 (e.g., during the forward flight) and/or the temperature T of the batteries is lower than the temperature threshold value T0, the control unit <NUM> is adapted to deactivate or keep the fans <NUM> deactivated. In this condition, the batteries <NUM> are cooled by the flow of air entering in the cooling system <NUM> through the opening <NUM> due to the effect of the relative motion of the aircraft <NUM> with respect to the air in which it is immersed. This type of cooling is called "ram ventilation".

Conversely, when the forward speed v is lower than the speed threshold value v0 (e.g., while hovering) and/or the temperature T of the batteries is greater than the temperature threshold value T0, the control unit <NUM> is adapted to activate the fans <NUM>. In this condition, the batteries <NUM> are cooled by the flow of air entering the cooling system <NUM> through the opening <NUM>, which is forced by the action of the fans <NUM>.

As shown in <FIG> and <FIG>, the opening <NUM> is arranged at the nose <NUM> and the openings <NUM> are arranged at the belly <NUM>.

In detail, the opening <NUM> is centred with respect to the median plane M (<FIG>).

Preferably, furthermore, the opening <NUM> comprises:.

In other words, the opening <NUM> has a curved elliptical shape, i.e. a bean shape.

The aircraft <NUM> further comprises three containers <NUM>, <NUM>, <NUM> defining respective inner volumes <NUM>, within which respective pluralities of batteries <NUM> are contained. The batteries <NUM> within each inner volume <NUM> define a plurality of interstices <NUM> with one another and the respective container <NUM>, <NUM>, <NUM>.

In the embodiment shown, the containers <NUM>, <NUM> and <NUM> are parallelepiped-shaped (<FIG>). In detail, the containers <NUM>, <NUM> and <NUM> have a square or substantially square base in a plane parallel to the axes X and Y. In addition, the extension of the containers <NUM>, <NUM>, and <NUM> parallel to the axis Z is smaller (e.g., <NUM>/<NUM> or <NUM>/<NUM>) than the extension of the containers <NUM>, <NUM>, and <NUM> parallel to the axes X and Y.

The containers <NUM>, <NUM>, <NUM>, moreover, are aligned with each other parallel to the axis Y and are centred with respect to the median plane M.

Preferably, the containers <NUM>, <NUM> and <NUM> are identical to each other.

The batteries <NUM> are shaped like an elongated parallelepiped along a direction K. The batteries <NUM> are furthermore parallel to each other, i.e. arranged so that the relative directions K coincide, and aligned with each other parallel to the axis X. In the embodiment shown, the directions K are parallel to the longitudinal axis Y. In addition, inside each container <NUM>, <NUM>, <NUM> the batteries <NUM> are fixed to each other.

In the embodiment shown, each container <NUM>, <NUM>, <NUM> contains five batteries <NUM>.

In detail, temperature T of the batteries <NUM> refers to the temperature at the outer surface of the batteries <NUM>, or in the vicinity of the batteries <NUM>, for example within the containers <NUM>, <NUM>, <NUM>.

As shown in <FIG>, <FIG> and <FIG>, the passage <NUM> comprises:.

In greater detail, proceeding from the opening <NUM> along the longitudinal axis Y towards the tail <NUM>, the duct <NUM> comprises a first section 30a and a second section 30b joined together.

The second section 30b is directed parallel to the longitudinal axis Y and the first section 30a extends obliquely with respect to the second section 30b. In detail, the opening <NUM> is arranged below the second section 30b with respect to the axis Z.

The second section 30b also has a circular cross-section and the first section 30a has a progressively variable shaped section. In detail, the shape of the cross-section of the first section 30a initially corresponds to the shape of the opening <NUM> and then connects to the circular section of the second section 30b (<FIG> and <FIG>).

Preferably, moreover, the passage section of the duct <NUM> has progressively decreasing extension proceeding from the opening <NUM> along the longitudinal axis Y towards the tail <NUM>.

In greater detail, the duct <NUM> fluidically connects the second section 30b to the inner volume <NUM> of the container <NUM> and is directed substantially parallel to the axis Z. The duct <NUM> fluidically connects the second section 30b to the inner volume <NUM> of the container <NUM>. The ducts <NUM> and <NUM>, moreover, are centred with respect to the median plane M.

The duct <NUM> fluidically connects the second section 30b to the inner volume <NUM> of the container <NUM> and comprises two branches 33a, 33b, which are arranged symmetrically with respect to the median plane M.

The cross-section of the duct <NUM> has a constant or substantially constant extension parallel to the axis Z. In addition, the ducts <NUM> and <NUM> have constant or substantially constant extension along the longitudinal axis Y.

The passage <NUM> also comprises two auxiliary ducts <NUM>, <NUM>, at which a respective fan <NUM> is housed (<FIG>).

Each of said auxiliary ducts <NUM>, <NUM> comprises respective mutually opposite ends 34a, 34b; 35a, 35b. These ends 34a, 34b; 35a, 35b are directly facing the duct <NUM> and in fluidic communication therewith (<FIG> and <FIG>).

In greater detail, the auxiliary ducts <NUM>, <NUM> are directly connected to the second section 30b of the duct <NUM>.

Considering a cross-section of the passage <NUM> passing through a plane orthogonal to the axis Z, the auxiliary ducts <NUM> and <NUM> are U-shaped and are arranged symmetrically with respect to each other with respect to the median plane M (<FIG>).

Each auxiliary duct <NUM>, <NUM> has a cross-section having an extension lower than the minimum extension of the cross-section of the duct <NUM>. In addition, the sum of the maximum extensions of the cross-sections of the auxiliary ducts <NUM> and <NUM> is lower than the minimum extension of the cross-section of the duct <NUM>.

As shown in <FIG>, the openings <NUM> have a rectangular section in a plane orthogonal to the axis Z, are arranged parallel to each other and to the longitudinal axis Y, and are spaced from each other parallel to the axis X.

In the embodiment shown in <FIG>, the containers <NUM>, <NUM> and <NUM> each comprise:.

The cover <NUM>, the base plate <NUM> and the set of side walls <NUM> of each container <NUM>, <NUM> and <NUM> define the inner volume <NUM> of the relative container.

In particular, the openings <NUM> are obtained at the base plate <NUM>.

Preferably, the covers <NUM> are fixed to each other and to the ducts <NUM>, <NUM> and <NUM> (<FIG>).

The aircraft <NUM> also comprises (<FIG>):.

Preferably, the sensor means <NUM> comprise a flow meter adapted to detect the flow rate that invests, in use, the aircraft <NUM> in parallel to a horizontal or substantially horizontal forward direction of the aircraft <NUM>.

The cooling system <NUM> further comprises means for varying the flow rate of air entering through the opening <NUM>, not shown.

Such flow rate variation means comprise, for example, a valve adapted to partialise the flow rate of entering air and operatively connected to the control unit <NUM>.

In detail, the control unit <NUM> is programmed to command the partialisation of the flow rate of air entering through the valve when the temperature T of the batteries <NUM> is lower than a minimum temperature threshold value Tmin, which is lower than the temperature threshold value T0. For example, the minimum temperature threshold value Tmin is equal to <NUM>.

The operation of the aircraft <NUM> according to the invention is described below.

In use, the aircraft <NUM> lands and takes off arranged in the second configuration with the rotors <NUM> arranged in the second position (<FIG>). In this second configuration, the lift required to sustain the aircraft <NUM> is provided by the rotors 3a, 3b and <NUM>.

During the transition from the first to the second configuration of the aircraft, the control unit <NUM> is programmed to reduce the thrusts generated by the rotors 3a and 3b as the axes F, G of the rotors <NUM> progressively approach a condition of parallelism with the axis Y and the speed v of the aircraft <NUM> increases.

The aircraft <NUM> moves forward at cruising speed in the first configuration with the rotors <NUM> arranged in the first position (<FIG>). In this first configuration, the lift required to sustain the aircraft <NUM> is provided for the most part at least by the half-wings <NUM> and/or by other aerodynamic surfaces arranged along the aircraft <NUM>. The rotors 3a and 3b can be deactivated if necessary.

During use, the sensor means <NUM> detect the temperature T of the batteries <NUM> and/or the sensor means <NUM> detect the forward speed v.

If the forward speed v is greater than the speed threshold value v0 and/or the temperature T is less than the temperature threshold value T0, the control unit <NUM> deactivates the fans <NUM> or keeps them deactivated.

In detail, when the fans <NUM> are deactivated, the air enters the cooling system <NUM> through the opening <NUM> due to the effect of the motion of the aircraft <NUM>, crosses the duct <NUM> and is distributed among the ducts <NUM>, <NUM> and <NUM> reaching the containers <NUM>, <NUM> and <NUM>. Within the inner volumes <NUM> of the containers <NUM>, <NUM> and <NUM>, the air flows in the interstices <NUM>, absorbing the heat of the batteries <NUM>, and then escapes from the openings <NUM>.

In greater detail, during the crossing of the passage <NUM>, the air flow transits largely through the second section 30b and minimally through the auxiliary ducts <NUM> and <NUM>, by virtue of the cross-sectional dimensions of these auxiliary ducts <NUM>, <NUM> with respect to the cross-sectional dimensions of the second section 30b.

Conversely, if the forward speed v is lower than the speed threshold value v0 (e.g. when aircraft <NUM> is hovering), or the temperature T exceeds the temperature threshold value T0, the control unit <NUM> activates the fans <NUM>.

In detail, when the fans <NUM> are active, the air passes through in order the same ducts it passes through when the fans <NUM> are deactivated. However, since the fans <NUM> are activated, the kinetic energy of the air is increased and the forced ventilation of the batteries <NUM> is achieved.

If during operation of the aircraft <NUM> the temperature T of the batteries <NUM> falls below the minimum temperature threshold value Tmin, the control unit <NUM> commands the partialisation of the entering air flow rate. In this way, the amount of heat removed from the batteries <NUM> is reduced.

An examination of the characteristics of the aircraft <NUM> shows the advantages that it allows obtaining.

Since the cooling system <NUM> comprises the fans <NUM>, which perform the forced ventilation when the forward speed v is lower than the speed threshold value v0 and/or when the temperature T exceeds the temperature threshold value T0, it is possible to effectively regulate the temperature of the batteries <NUM> of the aircraft <NUM>. This is particularly true when the aircraft <NUM> is hovering and the flow rate of air entering through the opening <NUM> is therefore limited or in any case characterized by low kinetic energy.

Since the opening <NUM> is arranged at the nose <NUM>, it is possible to maximize the flow rate of air entering through the opening <NUM> itself. At the same time, since the openings <NUM> are arranged at the belly <NUM>, the flow of air exiting the cooling system <NUM> does not disturb the aerodynamics of the aircraft <NUM>.

Since the fans <NUM> are respectively arranged in the auxiliary ducts <NUM>, <NUM>, the fans <NUM> when they are deactivated do not constitute an obstacle to the transit of air, which passes substantially undisturbed through the duct <NUM>.

It is clear that the aircraft <NUM> described and shown herein may be subject to modifications and variations without thereby departing from the scope of protection defined by the Claims.

The aircraft <NUM> could be a helicopter or a helicoplane.

At least some or all of the rotors 3a, 3b and <NUM> could be with variable pitch.

The passage <NUM> could comprise a single auxiliary duct <NUM>, <NUM>, or more than two auxiliary ducts <NUM>, <NUM>.

The cooling system <NUM> could comprise a single fan <NUM>, or more than one fan <NUM>. In particular, the cooling system <NUM> could comprise more than one fan <NUM> for each of the auxiliary ducts <NUM>, <NUM>.

The aircraft <NUM> could comprise one, or two containers <NUM>, <NUM>, <NUM>, or even more than three containers <NUM>, <NUM>, <NUM>. In addition, the containers <NUM>, <NUM>, <NUM> could not be aligned with each other.

The directions K of the batteries <NUM> could be arranged parallel to the axis X and the batteries <NUM> could be aligned with each other along the longitudinal axis Y. Additionally or alternatively, the openings <NUM> could be arranged parallel to each other and to the axis X and be spaced apart from each other parallel to the longitudinal axis Y.

Claim 1:
Aircraft (<NUM>) capable of hovering comprising:
- a fuselage (<NUM>) elongated along a longitudinal axis (Y) ;
- at least one rotor (3a, 3b, <NUM>) that is rotatable about an axis of rotation with respect to said fuselage (<NUM>) ;
- electrical drive means adapted to rotate said at least one rotor (3a, 3b, <NUM>);
- batteries (<NUM>) adapted to power said electrical drive means; and
- a cooling system (<NUM>) of said batteries (<NUM>) ;
said cooling system (<NUM>) comprising:
- a first opening (<NUM>) adapted to allow air to enter;
- a plurality of second openings (<NUM>) adapted to allow air to escape;
- a passage (<NUM>), which fluidly connects said first opening (<NUM>) with at least some of said second openings (<NUM>) ;
said batteries (<NUM>) being placed within said passage (<NUM>) and fluidically interposed between said first opening (<NUM>) and at least some of said second openings (<NUM>) ;
said cooling system (<NUM>) further comprising at least one fan (<NUM>) adapted to increase the kinetic energy of the air contained in said passage (<NUM>);
said fan (<NUM>) being operated, in use, when the forward speed (v) of said aircraft (<NUM>) with respect to the ground is lower than a speed threshold value (v0) and/or when the temperature (T) of said batteries (<NUM>) exceeds a temperature threshold value (T0);
wherein it comprises at least one container (<NUM>, <NUM>, <NUM>) defining an inner volume (<NUM>), inside which a plurality of said batteries (<NUM>) is contained; said batteries (<NUM>) inside said inner volume (<NUM>) defining a plurality of interstices (<NUM>) between one another and said container (<NUM>, <NUM>, <NUM>);
characterized in that said passage (<NUM>) comprises:
- a first duct (<NUM>), which extends starting from said first opening (<NUM>);
- at least one second duct (<NUM>, <NUM>, <NUM>), which branches off from said first duct (<NUM>) and fluidically connects said first duct (<NUM>) to the inner volume (<NUM>) of a respective said container (<NUM>, <NUM>, <NUM>); and
- said interstices (<NUM>).