ARRANGEMENT FOR VENTILATING A RAIL VEHICLE COMPARTMENT

[0001]The invention relates to an arrangement for ventilating a compartment in a rail vehicle in order to reduce a possibly harmful concentration of a gas in said compartment.

[0002]It is known to ventilate a compartment of a rail vehicle in a targeted way in order to reduce a gas concentration which is present there or arises there and which could be hazardous for the rail vehicle, for the vehicle driver, etc. until a permissible limit value is reached.

[0008]The refrigerant example will be described in more detail by way of example using FIG. 3 with reference to a driver's cab FR of a rail vehicle.

[0009]The driver's cab FR is cooled using a refrigeration machine on the basis of what is referred to as a “cold vapor process”. The refrigeration machine has, as annularly interconnected components, a compressor VERDI, an evaporator VERDA, a tension relief valve ENTSP, a liquefier VERFL and a refrigerant KM which flows through the components in different states of aggregation via a duct system.

[0010]In order to extract heat from the driver's cab FR, the evaporator VERDA is coupled to the latter—i.e. it is either arranged in the driver's cab or it is arranged externally to the driver's cab FR and is connected to the latter via an intermediate circuit ZWK, which is designed, for example, as a heat exchanger.

[0011]The driver's cab FR is connected to the surroundings of the rail vehicle via a ventilation system such that fresh air FRIL passes from the surroundings into the driver's cab FR and is mixed there with circulating air UML of the driver's cab FR.

[0012]Preferably, the supply of air and the mixing are supported by a first fan VENT11 which is arranged in the driver's cab FR. Alternatively or to support this, a second fan VENT12 is provided for the same purpose.

[0013]The mixed air is cooled via the coupling to the evaporator VERDA, i.e. heat is extracted from the mixed air with the aid of the intermediate circuit ZWK and/or the evaporator VERDA and supplied to the coolant KM. By means of the absorption of heat, the coolant KM evaporates and passes from the evaporator VERDA to the compressor VERDI.

[0014]In the compressor VERDI, the gaseous refrigerant KM is brought to a higher pressure level and to a higher temperature level. The gaseous refrigerant KM then passes from the compressor VERDI to the liquefier VERFL which is arranged in a dedicated compartment RA.

[0015]In the liquefier VERFL, the gaseous refrigerant KM is condensed. In the process, heat which is released is transmitted to compartment air in the compartment RA and passes via exhaust air ABL of the compartment RA into the surroundings of the rail vehicle.

[0016]For example, the compartment RA is arranged in the front region of the rail vehicle.

[0017]The liquefied refrigerant KM passes from the liquefier VERFL to the tension relief valve ENTSP. The liquid refrigerant KM is “relieved of tension” there, i.e. pressure is reduced and therefore the temperature level of the refrigerant KM lowered.

[0018]The liquid refrigerant KM subsequently passes from the tension relief valve ENTSP to the evaporator VERDA and the described cooling circuit begins again.

[0019]The mixed air cooled in the driver's cab FR is referred to as supply air ZUL and distributed in the driver's cab FR. A portion of the supply air ZUL passes as so-called outgoing air FOL back out of the driver's cab FR via a venting system into the surroundings.

[0020]The compartment RA with the liquefier VERFL is structurally separated from the driver's cab FR and connected to the surroundings of the rail vehicle via a ventilation system. Said ventilation system is designed in such a way that intake air ANSL originating from the surroundings is conducted via the liquefier VERFL and passes back again as exhaust air ABL to the surroundings of the rail vehicle.

[0021]Preferably, this air conduction is supported by a first fan VENT21 which is arranged in the compartment RE. Alternatively or to support this, a further fan VENT22 is provided in the compartment RE for the same purpose.

[0022]Due to operational stipulations and requirements, individual components of the refrigeration machine may be arranged at different locations or compartments of the rail vehicle that may not coincide either with the driver's cab FR or with the compartment RA.

[0023]It is known to use what is referred to as “HFO-1234yf” as a refrigerant in the refrigeration machine. This refrigerant in the gaseous state is a combustible, colorless gas with a weak odor and accordingly has the disadvantage that a leakage may not be noticed. Furthermore, in the (air) atmosphere of a compartment, it forms a persistent, environmentally harmful acid, namely trifluoroacetic acid.

[0024]It is also known to use propane as a refrigerant. Propane burns cleanly and does not form a persistent acid when it leaks, but does form a highly explosive mixture with air.

[0025]For a compartment in a rail vehicle, in which a critical gas concentration may occur, a safety assessment or a risk assessment is required. For a positive risk assessment, it has to be ensured that, in the event of relatively small leaks in components of the refrigeration machine, a mean gas concentration in the compartment has only a low level or falls short of a specified gas concentration level.

[0026]In the case of the arrangement described according to FIG. 3, this is achieved in that large amounts of intake air ANSL are continuously conducted through the compartment RA irrespective of whether the refrigeration machine is or is not in operation.

[0027]A disadvantage of this solution is that components involved in this conduction of air (e.g. filters, fans, duct components, housing parts, etc.) are subject to being operated continuously, which leads to increased wear, soiling and to an increased need for maintenance.

[0028]The same analogously applies to each compartment of a rail vehicle if a hazardous gas concentration could occur therein—for example due to the drive system, as described at the beginning.

[0029]It is therefore the object of the present invention to specify an improved arrangement for ventilating a compartment in a rail vehicle in order, with little outlay, to reduce a possibly dangerous or hazardous gas concentration in said compartment.

[0030]This object is achieved by the features of claim 1. Advantageous developments are specified in the dependent claims.

[0031]The invention relates to an arrangement for ventilating a compartment in a rail vehicle, the rail vehicle additionally having a passenger accommodation area.

[0032]In particular, the passenger accommodation area is considered to be a driver's cab of the rail vehicle.

[0033]The compartment to be ventilated contains a component which releases a gas concentration in said compartment in the event of a leak.

[0034]The passenger accommodation area is connected to the surroundings of the rail vehicle via a ventilation system such that fresh air passes from the surroundings into the passenger accommodation area, is mixed there with circulating air present in the passenger accommodation area and is subsequently distributed as supply air in the passenger accommodation area.

[0035]The passenger accommodation area is connected to the compartment via an air duct. The air duct is designed in such a way that a portion of the supply air is removed from the passenger accommodation area as outgoing air and conducted in a unidirectional direction into the compartment in order to reduce the gas concentration there or in order to ensure a specified (possibly minimal) gas concentration in said compartment.

[0036]“Unidirectional” is understood here as meaning that the outgoing air is conducted only in one direction, namely from the passenger accommodation area into the compartment.

[0037]This is preferably realized using a nonreturn valve which is, for example, an integrated constituent part of the air duct.

[0041]In a preferred development, the refrigeration machine carries out cooling using a cold vapor process.

[0042]In a preferred development, the refrigeration machine has, as annularly interconnected components, a compressor, an evaporator, a tension relief valve, a liquefier and the refrigerant, the refrigerant flowing through the components in different states of aggregation via a duct system.

[0043]In a preferred development, the liquefier of the refrigeration machine forms the component arranged in the compartment.

[0044]In a preferred development, further components of the refrigeration machine (the compressor and/or the tension relief valve) are likewise arranged in the compartment.

[0045]In a preferred development, the evaporator is likewise arranged in the compartment.

[0046]In a preferred development, the evaporator is coupled to the passenger accommodation area—i.e. the evaporator is at least partially arranged in the passenger accommodation area or the evaporator is arranged externally to the passenger accommodation area but is connected to the passenger accommodation area via an intermediate circuit.

[0047]In each case, heat is extracted from the circulating air, which is mixed with fresh air, and therefore from the passenger accommodation area and supplied to the refrigeration machine refrigerant which evaporates because of the supply of heat.

[0054]In a preferred development, the compartment is structurally and/or spatially separated from the passenger accommodation area.

[0055]In a preferred development, the compartment is arranged in the front region of the rail vehicle.

[0056]In a preferred development, the compartment is connected to the surroundings of the rail vehicle via a ventilation system so that the compartment is ventilated.

[0057]In a preferred development, the ventilation system of the compartment is designed in such a way that intake air originating from the surroundings is conducted via the component of the compartment.

[0058]In a preferred development, the outgoing air passes either on its own or together with the intake air as exhaust air into the surroundings of the rail vehicle.

[0059]In a preferred development, the supply of the outgoing air into the compartment is designed as a continuous supply such that, when a ventilation system of the compartment is inactive, the reduction in the gas concentration in the compartment or the maintaining of the specified gas concentration in said compartment is ensured via the outgoing air.

[0060]In a preferred development, the ventilation system of the compartment is designed in such a manner that the intake air originating from the surroundings is conducted via the liquefier for heat transfer purposes such that heat from the coolant is transferred via the liquefier to the intake air.

[0061]The present invention achieves minimal ventilation of a compartment in a rail vehicle with simple means and with little outlay. This minimal ventilation is sufficient to reduce a critical gas concentration which may be present or arises in said compartment to a negligible extent.

[0062]The present invention supports the use of an inflammable refrigerant in a refrigeration machine of a rail vehicle: a compartment which is considered to be critical is ventilated with simple means irrespective of whether a ventilation system provided for said compartment is or is not in operation.

[0063]The present invention reduces or avoids a previously necessary continuous operation of components (e.g. filters, fans, duct components, housing parts, etc.) of the ventilation system of the compartment.

[0064]The effect achieved by the present invention is that, in the event of small leaks, a clear safety margin of the gas concentration with respect to a lower explosion limit is set and maintained.

[0065]The effect achieved by the present invention is that an explicit risk assessment for a compartment can be dispensed with. Accordingly, costs are saved.

[0066]By means of the present invention, in particular by means of the nonreturn valve and by means of the arrangement of the component considered to be critical, the passenger accommodation area or the driver's cab is decoupled from the compartment in respect of the gas concentration.

[0067]As a result, the passenger accommodation area or driver's cab is additionally protected from the consequences of a leak from the component in the compartment.

[0068]By means of the specific distribution of the components of the refrigeration machine, the present invention prevents the inflammable refrigerant from entering the passenger accommodation area in the event of leaks.

[0069]By means of the present invention, a sustained use of an environmentally compatible but inflammable refrigerant is realized and the use thereof simplified.

[0070]The invention will be explained in more detail below by way of example with reference to a drawing, in which:

[0071]FIG. 1 shows an overview of the arrangement according to the invention with reference to a rail vehicle which has a refrigeration machine,

[0072]FIG. 2 shows some details regarding the arrangement according to the invention with reference to FIGS. 1, and

[0073]FIG. 3 shows the prior art described in the introduction.

[0074]FIG. 1 shows an overview of the arrangement according to the invention with reference to a rail vehicle which has a refrigeration machine.

[0075]A driver's cab FR as the passenger accommodation area is cooled with the aid of the refrigeration machine on the basis of what is referred to as a “cold vapor process”. The refrigeration machine has, as annularly interconnected components, a compressor VERDI, an evaporator VERDA, a tension relief valve ENTSP, a liquefier VERFL and a refrigerant KM which flows through the components in different states of aggregation via a duct system.

[0076]The evaporator VERDA is coupled to the driver's cab FR in order to extract heat therefrom—i.e. it is either arranged in the driver's cab or it is arranged externally to the driver's cab FR and is connected thereto via an intermediate circuit ZWK which is designed, for example, as a heat exchanger.

[0077]The driver's cab FR is connected to the surroundings of the rail vehicle via a ventilation system such that fresh air FRIL passes from the surroundings into the driver's cab FR and is mixed there with circulating air UML in the driver's cab FR.

[0078]Preferably, the supply of air and the mixing are supported by a first fan VENT11 which is arranged in the driver's cab FR. Alternatively or to support this, a second fan VENT12 is provided for the same purpose.

[0079]The mixed air is cooled via the coupling to the evaporator VERDA, i.e. heat is extracted from the mixed air with the aid of the intermediate circuit ZWK and/or the evaporator VERDA and supplied to the coolant KM. By means of the absorption of heat, the coolant KM evaporates and passes from the evaporator VERDA to the compressor VERDI.

[0080]In the compressor VERDI, the gaseous refrigerant KM is brought to a higher pressure level and to a higher temperature level. The gaseous refrigerant KM then passes from the compressor VERDI to the liquefier VERFL which is arranged in a dedicated compartment RA.

[0081]In the liquefier VERFL, the gaseous refrigerant KM is condensed. In the process, heat which is released is transmitted to compartment air in the compartment RA and passes via exhaust air ABL of the compartment RA into the surroundings of the rail vehicle.

[0082]For example, the compartment RA is arranged in the front region of the rail vehicle.

[0083]The liquefied refrigerant KM passes from the liquefier VERFL to the tension relief valve ENTSP. The liquid refrigerant KM is “relieved of tension” there, i.e. pressure is reduced and therefore the temperature level of the refrigerant KM lowered.

[0084]The liquid refrigerant KM subsequently passes from the tension relief valve ENTSP to the evaporator VERDA and the described cooling circuit begins again.

[0085]The compartment RA with the liquefier VERFL is structurally separated from the driver's cab FR and connected to the surroundings of the rail vehicle via a ventilation system. Said ventilation system is designed in such a way that intake air ANSL originating from the surroundings is conducted via the liquefier VERFL and passes back again as exhaust air ABL to the surroundings of the rail vehicle.

[0086]Preferably, this air conduction is supported by a first fan VENT21 which is arranged in the compartment RE. Alternatively or to support this, a further fan VENT22 is provided in the compartment RE for the same purpose.

[0087]Due to operational stipulations and requirements, individual components of the refrigeration machine may be arranged at different locations or compartments of the rail vehicle that may not coincide either with the driver's cab FR or with the compartment RA.

[0088]The mixed air cooled in the driver's cab FR is referred to as supply air ZUL and distributed in the driver's cab FR. A portion of the supply air ZUL is conducted as so-called outgoing air FOL out of the driver's cab FR via an air conduction duct LUFTFL into the compartment RA.

[0089]The air conduction duct LUFTFL as an air duct connects the driver's cab FR to the compartment RA.

[0090]Said air conduction duct LUFTFL is designed in such a way that a portion of the supply air ZUL is removed from the driver's cab FR as outgoing air FOL and conducted in a unidirectional direction into the compartment RA in order to reduce a gas concentration which may be present there.

[0091]FIG. 2 shows some details of the arrangement according to the invention that is shown in FIG. 1.

[0092]In the example shown here, the evaporator VERDA is part of the driver's cab FR, while the components VERDI, VERFL and ENTSP of the refrigeration machine are arranged within the compartment RA.

[0093]Preferably, the fresh air FRIL is mixed with the circulating air UML within a and air treatment device LUFTB, which has a channel-like system for conducting air.

[0094]The fresh air FRIL is sucked up via a first channel KAN1 of the air treatment device LUFTB, while the circulating air UML is sucked up via a second channel KAN2 of the air treatment device LUFTB.

[0095]The fresh air FRIL and the circulating air UML are mixed together via a connection of the two channels KAN1 and KAN2 and pass via a third channel KAN3 of the air treatment device LUFTB via the fan VENT11 arranged there to the evaporator VERDA.

[0096]The evaporator VERDA is arranged in the third channel KAN3 downstream of the fan VENT11.

[0097]The evaporator VERDA extracts heat from the supplied mixed air and cools the latter.

[0098]The cooled air then passes back again as supply air ZUL via the third channel KAN3 into the driver's cab FR. The supply air ZUL is heated again here and passes as circulating air UML to the air treatment device LUFTB.

[0099]Via the liquefier VERFL, heat is extracted from the coolant KM and passes with the aid of the exhaust air ABL out of the compartment RA into the surroundings of the rail vehicle.

[0104]The outgoing air FOL is extracted from the driver's cab FR preferably using a fan VENT13 which is arranged in the driver's cab FR.

[0105]In the compartment RA, the outgoing air FOL, possibly together with the intake air ANSL, forms the compartment air of the compartment RA which is therefore thoroughly flushed.

[0106]The thorough flushing by means of the outgoing air FOL is carried out continuously and irrespective of whether intake air ANSL passes into the compartment RA, whether same passes only in reduced form into the compartment RA or does not pass into the compartment RA.

[0107]Preferably, a nonreturn valve KLAP is integrated within the air conduction duct LUFTFL. Said nonreturn valve prevents air loaded with coolant KM from passing in predetermined or unfavorable pressure conditions from the compartment RA into the driver's cab FR.

[0108]The effect achieved via the described spatial separation of the components of the refrigeration machine is that possibly occurring leaks of the refrigeration machine are limited to the compartment RA.

[0109]The effect achieved by supplying the outgoing air FOL to the compartment RA is that, in said compartment RA, an air/refrigerant concentration possibly present or arising there is lowered.

[0110]The lowering has the effect that, for small leaks, there is a clear safety margin with respect to a lower explosion limit UEG. For small leak rates, an explicit risk assessment can then be dispensed with.