OVERCOMING A MALFUNCTION IN THE REFRIGERATING SYSTEM

DESCRIPTION OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates to the sector of railway transport with controlled temperature of goods, typically perishable goods, and more in particular of the transport of goods with railway vehicles provided with one or more refrigerating units for controlling the temperature and thus enable conservation of the cold chain. The temperature and the state of conservation of the goods depends on the specific application; typically the goods can be refrigerated or frozen.

DESCRIPTION OF THE PRIOR ART

Goods wagons have been for a long time well represented in the prior art and comprise one or more refrigerating units which enable transport of goods at a controlled temperature; an example is given in GB469095A. However the solutions utilised over recent decades are clearly differentiate from the one illustrated in GB469095A for both technical and commercial reasons. The container represents a self-standing unit, which, having to guarantee intermodality, cannot be functionally dependent on the specific wagon that transports it. Consequently a common practice is to provide the wagon with electrical connections internationally available, so as to connect the containers or the one or more refrigerating units associated to the container to them. Typically refrigerated containers, i.e. provided with a refrigerating unit, or refrigerating units, associated to the containers are supplied at 400 V in alternating current, which in the following will be referred-to as AC, including in the figures of the appended drawings. Again with reference to the accompanying figures, the term DC will be used to indicate direct current and Hi-V and Lo-V respectively indicated high voltage and low voltage, typically but not necessarily 400 V and 12 V. The connections of the refrigerating gas pipes in GB469095A are particularly delicate and a small error during the connection step might lead to the interruption of the cold chain, causing loss or degrading of the whole load.

Railway convoys for transporting goods at a controlled temperature often pass along non-electrified lines and/or stop in areas where it is not possible to guarantee an electricity supply. Further these convoys generally have a composition comprising many vehicles so that the transfer of electrical energy from the locomotive via electric cables is expensive, is subject to frequent faults and is at risk of vandalism and/or robbery. Further, the railway convoy can stretch over many hundreds of kilometres and several days of travel prior to reaching its destination.

The solution that in the present day is probably most employed is that of providing each container with electricity generators having an internal combustion motor and a fuel tank, alike to what occurs in road transport. This solution too is not without drawbacks, relating to both the management complexity and consumption, as well as environmental impact. For all the above reasons, transport on roads is generally preferred, and rail transport is substantially limited to the case in which the goods can be subjected to a constant increase in temperature in railway wagons with isothermal containers. Patent RU2711857C1 describes a system of electricity supply for railway refrigerating units and discusses the most relevant issues for the sector of rail transport of perishable goods.

There is therefore an established need for a railway convoy which responds to the present needs of the market in regard to control of the temperature along the whole journey regardless of the environmental conditions and the electricity supply of the convoy. Also required is the need for a railway convoy that is simple to manage and which reduces the risks deriving from vandalism and/or robbery. Further, there is also the need to prevent perishing of the goods due to faults.

SUMMARY OF THE INVENTION

An object of the present invention is to obviate the above-mentioned drawbacks of the prior art solutions.

A first aim is to provide a railway convoy independent of the availability of fuel and/or electricity supply. A second aim is to guarantee the continuity of the cold chain in the case of a fault in a vehicle of the convoy.

A further aim of some embodiments is to limit the impact due to the presence of the refrigerating units on the energy surge for the traction or thrust of the railway convoy.

Another aim of some embodiments is to guarantee the continuity of functioning of the refrigerating units even when the railway convoy is stationary or is moving at a very low speed.

A further aim of some embodiments is to simplify the operations in a case of a fault.

These and other aims, which will be obvious to the expert in the sector from a reading of the following text, are attained with a railway convoy for transporting goods at a controlled temperature and to a method for managing a fault in a railway convoy according to the claims.

In accordance with the teachings of the present document, the railway convoy comprises a first drawn and/or pushed vehicle an a second drawn and/or pushed vehicle. Both the first vehicle and the second vehicle comprise a frame, wheels which are rotationally connected to the frame, one or more containers for transporting goods arranged above the frame, one or more refrigerating units supplied with an electrical current for controlling the temperature internally of the one or more containers and an electric generator moved by at least a wheel and which supplies electrical current to the one or more refrigerating units.

The railway convoy advantageously comprises an electrical connection configured to connect the one or more refrigerating units of the second vehicle to the electric generator of the first vehicle and the electric generator of the first vehicle is dimensioned so as to contemporaneously supply electrical current to the refrigerating units of the first vehicle and the second vehicle so as to control the temperature of the goods in a fault condition of the second vehicle.

The method comprises steps of providing a railway convoy according to the present description, identifying a faulty component in the second vehicle, electrically detaching the faulty component from the one or more refrigerating units of the second vehicle and supplying the one or more refrigerating units of the second vehicle with the electrical energy converted by the electric generator of the first vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the invention will be described in the following part of the present description, according to what is set down in the claims and with the aid of the accompanying drawings, in which:

- figure 1 is a lateral view of a schematic embodiment of a railway convoy according to the invention;

- figure 2 is a schematic embodiment from above drawn and/or pushed vehicle of another embodiment of a railway convoy according to the invention; - figures 3 and 4 are perspective views from different angles of a portion of drawn and/or pushed vehicle of another embodiment of a railway convoy according to the invention;

- figure 5 is a view from above of the system of figure 4;

- figures 6 and 7 are functional electric diagrams of drawn vehicles of embodiments of railway convoys according to the invention;

- figures 8 and 9 are schematic illustrations of embodiments of a method for managing a fault according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the appended drawings, reference numeral 100 denotes a railway convoy for transporting goods at a controlled temperature.

An embodiment of the railway convoy (100) comprises a first vehicle (10) that is drawn and/or pushed and a second vehicle (20) that is drawn and/or pushed, commonly known as goods cars or wagons.

As is known to the technical expert, a railway convoy (100) comprises one or more locomotives (1 ) which draw and/or push the other vehicles (10. 20) which, for example, can be supplied electrically or by combustible liquids. The railway convoy (100) preferably comprises a plurality, typically ten or multiples of ten, of drawn and/or pushed vehicles (10, 20) which can be made according to the invention. Figures 1 , 8, and 9 illustrate, in broken lines, the connections between the locomotive (1 ), and the vehicles (10, 20) represent the presence of further vehicles; the railway convoy (100) can reach a length of one or more kilometres. Both the first vehicle (10) and the second vehicle (20) respectively comprise:

- a frame (11 , 21 );

- wheels (121 , 221 ) rotationally connected to the frame (11 , 21 ); - one or more containers (13, 23) for transporting goods arranged above the frame (11 , 21 );

- one or more refrigerating units (14, 24) supplied with an electrical current for controlling the temperature internally of the one or more containers (13,

23);

- an electric generator (15, 25) moved by at least a wheel (121 , 221 ) and which supplies electrical current to the one or more refrigerating units (14,

24).

The railway convoy (100) advantageously comprises an electrical connection (4), typically one or more electric cables, configured to connect the one or more refrigerating units (24) of the second vehicle (20) to the electric generator (15) of the first vehicle (10).

Further, the electric generator (15) of the first vehicle (10) is dimensioned to contemporaneously supply electrical current to the refrigerating units (14, 24) of the first vehicle (10) and the second vehicle (20) so as to control the temperature of the goods in a fault condition of the second vehicle (20).

The railway convoy (100) of the invention does not require long electrical connections across the wagons in order to guarantee the electricity supply and, at the same time, ensure maintaining the desired climate-control profile even in a case of a fault or tampering of one or more electrical or electronic components of a vehicle (10, 20). The railway convoy (100) according to the invention secures the energy demand of the containers (13, 23) in normal conditions by conversion of the mechanical energy available to the wheels (121 , 221 ) and also guarantees the continuity of the service for long journeys or periods when there has been a failure. The first vehicle (10) and the second vehicle (20) preferably both comprise two or more wheel sets (12, 22) rotationally connected to the frame (11 , 21 ) and comprising the wheels (121 , 221 ).

Clearly it is preferable for the electric generator (25) of the second vehicle (20) to be dimensioned alike to the one of the first vehicle (10) so as to guarantee the continuity of the desired climate-controlled conditions internally of the containers (13, 23) including in the case of a fault regarding the first vehicle (10).

In the case of a railway convoy (100) with a plurality of drawn and/or pushed vehicles (10, 20) made according to the teachings of the present description it is possible to guarantee, over time and often working in critical conditions, the transport of the goods in the desired climate-controlled conditions internally of the containers (13, 23). In fact, a railway convoy (100) of the type described would be able to successfully respond to a sequence of faults involving a plurality of drawn and/or pushed vehicles (10, 20).

As regards the technical effects of the invention already emerge in the minimum conditions indicated in the claims, and further benefits are obtained by implementing the teachings included in the present description also with regard to the second vehicle (20) and/or in the other drawn and/or pushed vehicles, more preferably in each drawn and/or pushed vehicle (10, 20) of the railway convoy (100).

Further, the electric generator (15, 25) might be dimensioned so as also to satisfy the refrigerating units (14, 24) of two or more drawn and/or pushed vehicles.

The electric generator (15) of the first vehicle (10) is preferably dimensioned to provide at least the combined maximum power absorbed by the refrigerating units (14, 24) of the first vehicle (10) and of the second vehicle (20). The electric generator (15) of the first vehicle (10) guarantees full functionality including in a faulty condition, enabling the railway convoy (100) to carry on with even long journeys.

More preferably the electric generator (15) of the first vehicle (10) is dimensioned so as to supply at least the combined maximum power absorbed by the refrigerating units (14, 24) of the first vehicle (10) and the second vehicle (20) at a velocity of the railway convoy (100) comprised between 4 km/h and 10 km/h. This last velocity, indicated with respect to the railway convoy (100) so as to be immediately comprehensible, can be transposed in terms of rotation velocity of the wheel (121 , 221 ), once the rolling radius is known.

The over-dimensioning of the electric generator (15) of the first vehicle (10) enables reducing the time periods in which the load of the refrigerating units (14, 24) is greater than what is available, limiting or annulling the risk of operating the containers (13, 23) in undesired climate-controlled conditions.

It is preferable for the electric generator (15) of the first vehicle (10), more preferably for also the electric generator (25) of the second vehicle (20), to be an axial-flux electric motor. The use of this type of motor guarantees the electrical power demanded though with a limited transmission ratio between the wheel (121 , 221 ) and the shaft of the electric generator (15) or between the axle of the wheel set (12) and the shaft of the electric generator (15). This is particularly significant when the electric generator (15) is over-dimensioned.

The example of figure 3 includes a pinion (91) which directly engages a cogwheel (90) solidly constrained to the wheel set (12). This coupling is particularly critical, especially when it is desired to guarantee good working life for the gearings in line with the working life of the railway convoy (100). Although other embodiments can comprise more complex gearboxes, the axial-flux electric motor reduces the technical requirements demanded of the gearings of the gearboxes. In fact, the axial-flux electric motor enables having a high number of poles available; in a case where the number of poles is equal to or greater than 12, the axial-flux electric motor can operate with a limited transmission ratio between the at least a wheel (121 , 221 ) and the shaft of the electric generator (15, 25) which does not require the introduction of gearboxes. Typically an axial-flux electric motor can be used directly with a transmission ratio (velocity of the at least a wheel (121 , 221 )) with respect to the velocity of the shaft of the electric generator (15, 25) greater than 1 :13 or 1 :14.

In the case of use of electric motors with a number of poles of less than 10 or even 12, the required transmission ratios are reduced and it is necessary to have special gearboxes or speed changes.

Preferably, the first vehicle (10), more preferably also the second vehicle (20), comprises an overdrive (92) interposed between the at least a wheel (121 , 221 ) and the electric generator (15, 25). In a preferred embodiment, the transmission ratio is varied on the basis of the rotation velocity of the electric generator (15, 25), which velocity is usually detected by the inverter (17, 27) described in the following.

For example, the overdrive (92) can have a first transmission ratio of 1 :26 or 1 :28 and a second transmission ratio of 1 :10 or 1 :12. The first transmission ratio is used up to a speed of at least a wheel (121 , 221 ) corresponding to a speed of the railway convoy (10) of at least about 30 km/h while the second transmission ratio is used beyond this speed. The overdrive (92) is typically electrically controlled.

In figure 3, the support (80) of the electric generator comprises an extensible arm coupled on one side by a spherical joint to a beam of the vehicle (10, 20) on the other side to the electric generator (15, 25) - inverter (17, 27) unit. This unit is supported by a hollow cylinder rotationally connected to the axle of the wheel set (12, 22). With the above-described configuration, the electric generator unit (15, 25), is not set in rotation by the axle of the wheel set (12, 22) and at the same time is movable with respect to the beam and to the frame (11 , 21 ). A like configuration is also visible in figure 2 in which the electric generator (15, 25) - inverter (17, 27) - overdrive (92) unit is directly connected to the frame (11 , 21 ).

The first vehicle (10) and the second vehicle (20) preferably both comprise two or more containers (13, 23) and two or more refrigerating units (14, 24), more preferably each refrigerating unit (14, 24) is functionally associated to a respective container (13, 23).

Figure 1 includes a configuration by way of example of the first vehicle (10) and the second vehicle (20) that is particularly advantageous as two containers (13, 23) are transported in each of the vehicles (10, 20), of about 15 metres each with frozen goods. Taking for example a maximum electricity consumption of 10 kW per container (14, 24) and an average of 6kW, an electric generator (15) of the axial-flow type motor with a maximum power of around 120 kW would satisfy the teachings of the present invention as already at a reduced speed it would guarantee 50kW, i.e. the peak instantaneous power beyond a safety margin, available in reserve for recharging an electric accumulator (18) as illustrated in the following.

The presence of an electric accumulator (18, 28) is particularly significant in the case of prolonged stops, even if only for loading/unloading, or in the of long crossings at especially low speed, conditions frequently occurring with goods transport. Frozen transports are subject to temperature oscillations that are less sharp and can also operate without electric accumulators (18, 28). Figure 6 shows, by way of example, an electric system without an accumulator (18, 28) and in figure 7 another system which is equipped with one. Although figures 6 and 7 respectively relate to the first vehicle (10) and the second vehicle (20), this is not strictly necessary, indeed, both the first vehicle (10) and the second vehicle (20) preferably share the same configuration.

Both the first vehicle (10) and the second vehicle (20) preferably comprise an electric accumulator (18, 28), an inverter (17, 27) between the electric generator (15, 25) and the electric accumulator (18, 28) and a management system of loads (16, 26) which manages the load demanded of the electric generator (15, 25). Typically the inverter (17, 27) is of the AC/DC/AC type.

The management system of the loads (16, 26) can be of the hardware and/or of the software type; in the figures this is indicated with the English acronym HWSW. Usually, regardless of the presence of the electric accumulator (18, 28), the output of the electric generator (15, 25) is connected to the inverter (17, 27) which maintains the frequency constant in output the one or more refrigerating units (14, 24). In general, to oppose the variation of frequency due to the variation in velocity of the railway convoy (100) the output of the electric generator (15, 25) is rectified with a passage from AC to DC and then reshaping the output with a constant shape, for example AC at 50 Hz. Downstream of the transformation to DC, a dedicated electric accumulator, for example a super capacitor or a mini battery, can be positioned to guarantee stability of the voltage in DC condition, useful in a case of strong transients of the electric generator (15, 25).

More complex and expensive solutions might include an inverter (17, 27) which directly modifies the frequency to the desired value. The management system of loads (16, 26) is preferably configured to supply the electric accumulator (18, 28) only after the electric generator (15, 25) has matched the load of the one or more refrigerating units (14, 24).

The electric generator (15, 25) according to the invention is dimensioned to directly satisfy the demands of the one or more refrigerating units (14, 24) without requiring further electrical conversions, as would happen in the case where the electric accumulator (18, 28) were previously charged.

The management system of loads (16, 26) is preferably configured to detach from the electric generator (15, 25) the one or more refrigerating units (14, 24) and the electric accumulator (18, 28) when the at least a wheel (121 , 221 ) which drives the electric generator (15, 25) starts to rotate from a stationary position. In this condition the one or more refrigerating units (14, 24) can possibly be powered by the electric accumulator (18, 28). The railway convoy (100) is thus not negatively affected by the presence of the electricity generators (15, 25) at the most critical moment of the surge, when a significant torque is required.

Both the first vehicle (10) and the second vehicle (20) preferably comprise an electrical connector (19, 29) connected between the inverter (17, 27) and the electric accumulator (18, 28) and an electric switch (30) arranged between the electric accumulator (18, 28) and the electrical connector (19, 29) so that the electric accumulator (28) of the second vehicle (20) is detachable from the inverter (27) of the second vehicle (20) and is connectable to the electric accumulator (18) of the first vehicle (10).

In the case of a fault in the electric accumulator (28) of the second vehicle (20), the one or more refrigerating units (24) of the second vehicle (20) can in any case receive electrical energy from the electric accumulator (18) of the first vehicle (10). The railway convoy (100) more preferably comprises a further electrical connection (5), typically one or more electric cables, the electrical connector (19, 29) comprises an opening device (191 , 291) for opening the electric switch (30) and the further electrical connection (5) has only a first end (51 ) of the two ends that is configured to activate the opening device (191 , 291 ) after the electrical connector (19, 29) has been coupled.

The further electrical connection (5) thus guarantees the detaching of the faulty electric accumulator (28, 18), ensuring the connection between the functioning electric accumulator (18, 28) and the one or more refrigerating units (14, 24) of the of the respective vehicle (20, 10) that are faulty. At the same time, the operator, typically the driver of the railway convoy (100), is prevented from performing incorrect operations that might compromise the functioning of further components.

Both the first vehicle (10) and the second vehicle (20) preferably comprise a charging system (60) of the electric accumulator (18, 28) of the on-board type having an input connector (61 ). In this way the possibilities of response in the case of faults are multiplied, for example in the case of a fault in the inverter (17, 27). The input connector (61 ) is typically an earthed single-phase or three-phase AC socket.

Both the first vehicle (10) and the second vehicle (20) preferably comprise an electric socket unit (70) in parallel with one another which is connected to the electric generator (15, 25) for supplying the one or more refrigerating units (14, 24) of the respective vehicle (10, 20) and an additional electric switch (31 ) arranged between the inverter (17, 27) and the electric socket unit (70). A first socket (71 ) of the electric socket unit (70) comprises an opening device (72) for opening the additional electric switch (31 ) and the electrical connection (4) has only a first end (41 ) of the two ends that is configured to activate the opening device (72) after the first socket (71 ) has been coupled. The first socket (71 ) represents an electrical connector which can supply or receive energy.

In the case of a fault in the second vehicle (20) the operator can reset the electricity supply with the use of the electrical connection (4), rapidly and without performing potentially damaging operations.

Multiple embodiments of the opening device (191 , 291 ) and of the opening (72) for opening the first end (41 , 51 ) are possible. In a preferred embodiment the first end (41 , 51 ) comprises an element which engages a mechanical guide so as to activate the electric switch (30) or the additional electric switch (31 ) following the coupling between the first end (41 , 51 ) and the first socket (71 ) or the electrical connector (19, 29). The first end (41 , 51 ) is denoted with a poka-yoke in figures 8 and 9.

In another embodiment the active coupling activates a relay which opens the electric switch (30) or the additional electric switch (31 ). Downstream of the relay there can be a high/low voltage conversion device.

As illustrated in the foregoing, the preferred embodiment of the connection (4) and of the further connection (5) avoid having to act manually and/or via a control system on the single switches in order to detach parts of the electric circuit and thus prevent further damage due to incorrect procedures.

As illustrated in figure 7, the electrical connector (19, 29) might be used also in the case of a fault in the electric generator (15, 25), by detaching (or not) the electric accumulator (18, 28).

The railway convoy (100) preferably comprises a control system, shown by way of example in figures 8 and 9, which signals the presence of faults and, possibly, actuates the first actions for conserving the continuity of the service. This control system is typically realised by wireless communications.

The invention also relates to a method for managing a fault in a railway convoy (100).

An embodiment of the method comprises steps of:

- providing a railway convoy (100) according to the present description;

- identifying a faulty component in the second vehicle (20);

- electrically detaching the faulty component from the one or more refrigerating units (24) of the second vehicle (20);

- supplying the one or more refrigerating units (24) of the second vehicle (20) with the electrical energy converted by the electric generator (15) of the first vehicle (10).

As illustrated above, the electrical detachment can take place with a sequence of manual and/or automatic operations or using the preferred embodiments of connection (4) and further connection (5).

Figures 8 and 9 are examples of the steps of the method applicable, for example, to vehicles (10. 20) configured as in figures 6 or 7. After a fault has been identified, for example with a signal on a tablet, by the control system, the driver can reset the functioning of the one or more refrigerating units (14, 24) involved with the fault.

Preferably the step of electrically detaching the faulty component and the step of supplying the one or more refrigerating units (24) can be realised contemporaneously, for example by inserting the first end (41 , 51 ) and the first socket (71 ) or in the electrical connector (19, 29) as illustrated in the foregoing.

In the case of figure 8, the fault relates to the electric accumulator (28) of the second vehicle which is detached from the inverter (27) using the opening device (291 ) and the electric switch (30); the electric accumulator (18) of the first vehicle (10) is thus connected to the inverter (27) of the second vehicle (20).

In the case of figure 9, the fault can relate to the electric generator (25) or the inverter (27) of the second vehicle which is detached from the electric socket unit (70) using the opening device (72) and the additional electric switch (31 ); the inverter (17) of the first vehicle (10) is thus connected to the electric socket unit (70) of the second vehicle (20).

Owing to the foregoing, it is preferable that during the step of electrically detaching the faulty component the electric accumulator (28) is also detached from the inverter (27) or the one or more refrigerating units (24) from the inverter (27).

It is understood that the above has been described by way of non-limiting example and that any constructional variants are considered to fall within the protective scope of the present technical solution, as claimed in the following.