WO2014133438A1

WO2014133438A1 - De-icing device for railroad switches and methods for de-icing

Info

Publication number: WO2014133438A1
Application number: PCT/SE2014/050223
Authority: WO
Inventors: Roland BÅNG
Original assignee: Infranord Ab
Priority date: 2013-02-28
Filing date: 2014-02-24
Publication date: 2014-09-04
Also published as: SE1350235A1; SE537766C2

Abstract

The present invention refers to a de-icing device for removing of snow and ice from railway switches. The device includes air treatment means having pressurizing means (45) and conduit means (5, 6) for conduction of the pressurized air to selected areas of the switch. According to the invention the air treatment means also includes drying means (42) for drying the air. The invention also refers to a method for removing of snow and ice from railway switches, by exhausting air to selected areas thereof. According to the inventive method the exhausted air is dried.

Description

DE-ICING DEVICE FOR RAILROAD SWITCHES AND METHODS FOR DE- ICING

Technical field

According to first aspect the present invention refers to a de-icing device for removing of snow and ice from railway switches, the device includes air treatment means having pressurizing means and conduit means for conduction of the pressurized air to selected areas of the switch.

In a second aspect the invention also refers to a method for removing of snow and ice from railway switches, where air is exhausted to selected areas of the switch.

Background of the invention

It is a commonly known problem that operation disturbances occur during winter time at switches in railway nets due to accumulation of snow and ice therein. Of course mainly this is the matter for countries having a winter climate where the temperature often is on the minus side.

The problems occur due to that ice and snow is accumulated at sensitive parts in the switch, such as between the point, the stock-rail and rod pits, in movable crossings and on glide plates. Partly it is a question of snow directly accumulated from the snowfall. Furthermore it is the case that ice and snow lumps often are formed at the components of the chassis frames of the train coaches such as bogies etc. When the coaches pass a switch it gives rise to vibrations such that the lumps came loose and fall down into the switch.

Operation disturbances caused by switches covered up of snow and ice cause enormous troubles with attendant costs. Therefore it is much important to remove or at least to reduce the problem. Several attempts have been made in this respect but yet no satisfying solution has been achieved.

Of course a manual clearance is possible but is impractical at distant places and furthermore it involves a moment of danger. Another applied method to keep away with snow and ice is to make use of electric switch heaters installed along the point and stock-rail and in the rod pits. The control possibilities are however unsatisfying and the heating time is long, which imply that the heating often is to be applied continuously independent of the demand. Large energy amounts are consumed and the costs will be inacceptable high. Furthermore lags are used, e.g. fibre board covers at the exterior of the stock-rails and tarpaulins on the points against the track centre as well as snow screens/fences and brushes. A great many of these solutions are impractical and often only remove some of the sources to the snow and ice problems.

Furthermore it is known per se to exhaust air to keep the switches free from snow and ice. A representative sample of the air exhausting technique to keep the switches free from snow and ice is described in US 3 697 746. An aggregate arranged next to the switch is described for generating heat pressurized air to be used for clean exhausting. The air is conducted by a transverse conduit means under one of the rails into longitudinal distribution conduits between the rails. From the distribution conduits there are transverse distribution channels to the spaces at the rails which need to be clean exhausted.

Further samples of this technique are described by US 2 898 062, US 3 697 746, US 4 081 161 , US 4 674 718, US 4 695 017, US 6 065 721 , US

2008/0084058, SE 388 886, SE 459 867, CN 1 035 149, CN 1 624 246 and CN 2 730 936.

A difficulty at the prior known devices is however that the relatively heat air will be cooled in contact with the parts of the switch and generate condensate from the air which is freezing and thereby ice is delivered to the area of the switch into which the air is exhausted. In worst case the clearing exhausting from snow can be contra productive by the ice generated from the air being cooled in contact with the rails and components of the switch belonging thereto.

The purpose with the present invention being based on the air exhausting technique is to improve such devices known per se and to overcome the problem with ice generation from condensate of the exhausted air.

By de-icing in the present application it is to be understood a removal of snow as well as ice and also to prevent that snow and ice is accumulated.

By longitudinal and transverse in the present application it is to be understood the direction mainly in parallel to and right across the rails,

respectively.

Summary of the invention The purpose set up is achieved according to the first aspect of the invention in that a device of the type mentioned above includes the distinctive features mentioned in the characterizing part of claim 1 . Thus, the air treatment means includes drying means for drying the air.

By the drying the moisture of the supplied air is lowered. When the air reaches the de-icing places and is cooled there, the lower moisture content of the air results in that no condensate or at least a substantially reduced condensate is generated. Thereby no or very little ice is added to the treated places. Thanks thereto it will be possible to make use of the air exhausting technique for an effective and rational de-icing of the switches. By the drying the problem with condensation water flowing down and freezing under the sleepers is eliminated or at least reduced. Otherwise such freezing will cause bad rail conditions and considerable stresses in the switch, which imply that the reverse device is jamming.

Tests have shown that an effective de-icing can be made in a very short time with the inventive device.

According to a preferred embodiment of the inventive de-icing device the air treatment means also includes a heating means for heating of the air.

The de-icing is made most effective in combination with heating and exhausting. Some heat is generated in the air at the pressurising due to the friction heat generated in the pressurising means, e.g. a fan. In many cases the friction heat delivered to the air is enough for sufficient removal of the snow and ice by the heat together with the exhausting. Furthermore the efficiency is increased by active heating of the air. The warmer air the more is the tendency of condensation. Therefore the invention is important especially in applications where the air is actively heated.

According to a further preferred embodiment the conduit means includes a supply conduit means connected to an air treatment means, a distribution supply conduit means connected to the supply conduit means and an allocation conduit means with an exhaust conduit means connected to the distribution conduit supply means, whereby the distribution conduit means is arranged between the switch related rails and proceeds mainly in parallel therewith.

Owing to that the distribution conduit supply means is arranged between the rails there is no need to require the area outside these for air distribution. In such a way one avoids interference with other types of equipment often to be found there. Furthermore the service people require being able to move around without obstacles outside the rails and therefore the arrangement inside the rails reduces the risk of accidents.

According to a further preferred embodiment the allocation conduit means includes a number of allocation conduits, each one provided with at least one exhaust opening.

Owing to that the allocation conduit means includes a number of allocation conduits it is facilitated to allocate the air in an optimum way onto exactly those areas where snow and ice arise in first hand and where it can cause service interruptions. In that the air exhausting may be concentrated to the most sensitive areas it is avoided to exhaust clearing areas where snow and ice does not involve any obstruction. Thereby one obtains an energy saving efficiency. In most cases it is most suitable to use one exhaust opening only from each one of the allocation conduits. However in some cases it can be suitable that an allocation conduit has a number of exhaust openings.

According to a further preferred embodiment each one of the exhaust openings is arranged to be directed onto a respective selected area, those areas including glide plates, support cleats and the space between the point and the stock-rail.

The directed exhausting involves that the air exhaust can be concentrated onto just those areas being critical, such that unnecessary waste of air exhaust onto less sensitive areas is avoided. It implies that the device will be very energy effective. Above all it is those areas defined above where the de-icing is important and useful.

According to a further preferred embodiment the allocation conduit means includes allocation conduits describing an angle of 45 to 90 degrees in relation to the distribution conduit supply means.

Normally it is most effective that the allocation conduits run in the transverse direction to minimize the total length of the conduits and in a rational way allocate the air to intended areas. Most suitable is that they mainly are transverse, i.e. describe an angle in the interval of 80 to 90 degrees. According to a further preferred embodiment the allocation conduits include such allocation conduits which start from opposite sides of the distribution conduit means.

It is a simple way to allocate the air to the rails at each side thereof when required. In most cases when only one side of the switch has to be treated, it is however enough to bring the allocation conduits at one side only.

According to a further preferred embodiment the distribution conduit means has a width being 1 .5 to10 times as large as its height.

It is important that the conduit laying between the rails is in such a plane being in safe distance below the top area of the rails not to interfere with the bottom side of the trains or to be an obstruction for different types of service tools which require the space between the rails. An headroom of about 80 mm up to the top area of the rails is necessary. In the same time it is suitable that the distribution conduit means can be resting on the sleepers to avoid detailed construction measures. This implies that available height for the distribution conduit means is fairly restricted as the top area of the rails lies about 170 mm above the top area of the sleepers. By designing the distribution conduit means with a comparatively wide sideways extension it is made possible to obtain a satisfactory flow area in spite of the restricted vertically space. Suitably each one of the distribution conduits of the distribution conduit means has the shape of a box with a

rectangular cross-section.

According to a further preferred embodiment the distribution conduit means includes only one distribution conduit.

It will minimize the need of total conduit laying. Of course it will result in somewhat longer allocation conduits. However only in a small degree as the distribution conduits of other reasons have to be arranged at least 500 mm from the nearest rail. At this embodiment having only one distribution channel it is suitably arranged centred between the rails.

According to a further preferred embodiment the distribution conduit has a single longitudinal channel for the air distribution.

In most cases it is only against one side of the switch the air has to be exhausted and in such a case it is most suitable to distribute the air through a single channel. In those cases the distribution conduit can be arranged somewhat closer to the side against which the air has to be exhausted. According to a further preferred embodiment, when the distribution conduit means includes only one distribution conduit, it is equipped with an inner longitudinal vertical wall separating the distribution conduit in two parallel channels.

In such a way the distribution conduit is separated in two parallel conduit parts, resulting in a more harmonic and controlled flow. By closing the input to one part of the distribution conduit, e.g. by a valve, it is possible in a simple controllable way to direct the exhaust against only one side of the switch, which is favourable when the need of de-icing, as sometimes is the case, is different for the different sides.

According to a further preferred embodiment the distribution conduit mainly has a rectangular shape.

It will optimize the use of the restricted space being available with respect to obtain required flow area.

According to a further preferred embodiment the supply conduit means and/or the distribution conduit means includes outside walls having a layer of isolating material at the inside thereof.

Thereby the cooling rate of the air is reduced as it flows from the air treatment device to the allocation conduits. It is particularly advantageous in connection with the present invention where by drying a high temperature is made possible of the exhausted air without the negative consequences mentioned above.

According to a further preferred embodiment the distribution conduit means includes air heating elements.

This contributes further to maintaining of a high temperature of the exhausted air, which of the same reason as mentioned just above is particularly advantageous in connection with the present invention. The additional heat supply relatively close to the exhaust areas improves the de-icing considerably. Having the air dried contributes to the possibility to increase the temperature of the air to be exhausted. Suitably the heating elements are of electrical type. The heating elements may be arranged along the whole distribution conduit means or only along parts thereof.

According to a further preferred embodiment each heating element is in form of a lining arranged on the inside of each one of the conduit walls. This contributes a smooth distribution of heat.

According to a further preferred embodiment each one of the distribution conduits of the distribution conduit means is made up of elongated modules, said modules being arranged to be connected with each other and loosened from each other in situ.

The module construction contributes to low construction costs and a great flexibility. Different switches may involve different need of the length of the conduit of the conduit lay out depending on type of switch and climate. The module construction involves that the same components can be used in these different connections which implies a rational managing. Modifications are also easy to be made in situ and to lengthening and shortening of the distribution conduit.

According to a further preferred embodiment the allocation conduit means includes at least an allocation conduit, the part of which closest to the exhaust opening goes in another direction than the rest of the allocation conduit.

Certain areas to be clear exhausted may be so localized and positioned that a crossway exhausting opening is not suitable. By slanting the allocation conduit in this way close to the exhausting opening also these areas are easy to reach in an effective way. In those cases it is often the question of an exhaust direction in the length direction. By aligning certain exhausting openings in such a way the air can be exhausted between the point and the stock-rail, such that a longitudinal turbulent channel is formed between the same, which very effective keeps drift snow away and vaporizes water, ice and snow.

According to a further preferred embodiment the conduit means is housing components to be used for other service functions than air exhausting.

In that way the conduit lay out can fulfil also other purposes and eliminate the need of certain installations therefore. For instance it can be the question of electric cables or signal circuits located in the conduits for the air.

The purpose set up is achieved according to the second aspect of the invention in that a method of the type mentioned above includes the particular measure taught by the characterizing part of claim 19. Thus the air to be exhausted is dried.

The device according to the invention may be controlled, checked up and supervised manually or automatically. By an automatic control etc. sensors may detect different parameters having effect on the demand for clearing exhaust and generate necessary control and information signals. For instance the sensors can relate to temperature, moisture and/or position. The control of different functions of the device can be done individually or co-ordinated and relate to e.g. the heating, pressure and/or dehumidification intensity of the air treatment unit, the flow shape in the conduit means by operation of valves, dampers, throttles etc. Also other functions such as the heating in the distribution channel means may be regulated in a corresponding way. Of course the regulation may include a simple ON/OFF control of each working parameter. A manual control may be made at the device itself, e.g. in a service house housing the air treatment means, or be remote controlled, eventually wireless. A manual control requires no sensors, but of course it is of advantage making use thereof also in that case. By remote control values detected by the sensors are transmitted wireless to the operating place.

According to preferred embodiments of the inventive method it is carried out by the invented device, in particular according to any of the preferred embodiments of the same.

The inventive method involves advantages of corresponding type as for the invented device and the preferred embodiments thereof and being explained above.

The advantage embodiments of the invention mentioned above are taught by the dependent claims. It may be understood that further preferred embodiments can be made by every possible combination of the preferred embodiments mentioned above and by every possible combination thereof with characteristics given in the description of embodiments below.

The invention is explained more closely by the detailed description below with examples thereof and with references to the drawings enclosed.

Brief description of the drawings

Fig. 1 shows a schematic general picture of a railway switch provided with a de-icing device according to the invention.

Fig. 2 shows schematically the air treatment means and its connection with the conduit means at the device according to Fig. 1 .

Fig. 3 shows a cross-section along line Ill-Ill in Fig. 1 .

Fig. 4 shows a cross-section along line IV-IV in Fig. 1 .

Fig. 5 shows a view in perspective of a modular distribution conduit according to the invention. Fig. 6 shows a top view of a detail of the de-icing device according to the invention.

Fig. 7 shows a top view of an alternative embodiment of a detail of an device according to the invention.

Fig. 8 shows a cross-section along line VIII-VIII in Fig. 7.

Fig. 9 shows a view in perspective of a detail of a device according to the invention.

Fig. 10 shows a view in perspective of a further detail of a device according to the invention.

Fig. 1 1 illustrates by a top view a railway switch provided with a device according to the invention.

Fig. 12 shows an enlarged view of a part of Fig. 1 1 .

Description of embodiments

Fig. 1 shows in a schematic way a railway switch with a de-icing device according to the invention. The rails of the main track are denoted 1 a, 1 b, the rails of the switch track are denoted 2a, 2b and the switch points are denoted 3a, 3b.

At the side of the switch there is a service house 40 housing an air treatment device 4. It exhausts hot, dehumidified air through a supply conduit 5 to a distribution conduit 6 situated between the rails 1 a, 1 b of the main track. The distribution conduit 6 goes mainly along the whole length of the switch and communicates with a number of allocation conduits 7, 8 going from the

distribution conduit 6 to the areas of the switch where the hot air is to be exhausted.

As shown in Fig. 2 there are air treatment devices 42, 45 inside the service house for the air to be exhausted against the switch. The air treatment devices include a dehumidifier 42 and a fan 45. The dehumidifier 42 has an inlet 42 communicating with the surrounding. Through an outlet 43 from the

dehumidifier 42 dried air is conducted into the service house 40. The fan 45 has an inlet 46 inside the service house 40 through which dried air is sucked into the fan, where it is pressurized and exhausted through the outlet 47 thereof.

By the passage through the fan 45 the air is somewhat heated by the friction heat generated therein. This heating may be complemented by further supply of heat to the air. In the figure it is symbolized by an electric heater 49 arranged in the fan outlet 47. Of course the heating may be made in another way too and arranged in another place of the air flow path.

Inside the service house there is also a control device 48 for control, checking up and supervision of the de-icing device. The control device 48 is arranged to be able to regulate the drying intensity of the dehumidifier 42 and of the pressure and flow from the fan 45. The control device may also include means for control of other functions of the de-icing device away in the conduit system.

The control function is represented by the arrows 48 emanating from the control unit 48. The control device 48 receives also signals representative by the arrows directed into the control device. They indicate the status of different parameters related to the switch and de-icing device.

By the control device 48 an all-automatic control of the de-icing device can be made. The control device is suitably equipped with a transmitter and a receiver for wireless transmission of information to and control signals from a supervision centre. From the centre manual control can interfere with the automatic control or replace it.

The hot and dry air from the fan outlet 47 is conducted into the supply conduit 5. It is equipped with an isolating layer surrounded by a protective cover and is situated at the road bed between the sleepers 9 such that it passes under the rail 1 a. The supply conduit 5 is connected with the downside of the distribution conduit 6 for transfer of the air thereto.

Fig. 3 shows a cross-section of the distribution conduit 6 at the area for its connection with the supply conduit 5. The distribution conduit 6 is divided in two parallel channels 63a, 63b separated by a vertical intermediate wall 66, where each one of the channels supplies air to a different side of the track. The distribution conduit has an external cover 61 of protective material, e.g. metal or plastic. Inside the cover there is a layer 62 of isolating material, also forming the intermediate wall 66.

An optional possibility is also shown in Fig. 3 to make use of the conduit system for other functions than distribution of air for de-icing. Thus in the channel 63a there is an electric cabling 68 for energy distribution and/or for signals to control and information transfer. The electric cables can be used for functions related with the de-icing but may as well be used for quite another function for operation and monitoring of the switch. In this way also other types of service circuits can be housed in the conduit system.

Inside each channel 63a, 63b there is an electric heater mat 64a, 64b for heat supply. The figure shows the heater mats surrounding the whole channel in the circumference direction, but alternatively they can be arranged at one or some of the channel sides only. The heater mats 64a, 64b can extend along the whole length of the distribution conduit, along a part thereof or along some sections thereof.

At the connection of the supply conduit to the distribution conduit there is a damper 65a, 65b at the inlet to respective channel 63a, 63b. By the dampers 65a, 65b the air supply to the one or other channel cut off. The figure shows the damper 65a in an open conduit, such that air flows into the channel 63a and the damper 65b in a closed position blocking the air flow to the channel 63b. In a more sophisticated embodiment the dampers can be made to be placed in intermediate positions between the completely closed position and the completely open position to regulate the air quantity to respective channel 63a, 63b.

The dampers 65a, 65b just as the heat supply to the heater mats 64a, 64b are regulated by the control device 48 in the service house 40.

The distribution conduit 6 has a rectangular cross-section with its length side in horizontal direction. It rests on the sleepers and has a height such that its top side stay somewhat below the rails head, about 90 mm. The outside dimensions of the distribution conduit is for instance 80 χ 300 mm.

As shown in Fig. 1 the air is conducted from the distribution conduit 6 to a number of allocation conduits 7, 8 on each side of the distribution conduit. Fig. 4 shows a cross-section view of the distribution conduit 6 and the allocation conduits 7, 8 at a connection place therefore. From the channel 63a an allocation conduit 7 emanates for an area in connection with the rail 1 a and from the channel 63b an allocation conduit 8 emanates for an area in connection with the other rail 1 b. Each one of the allocation conduits 7, 8 has an outlet opening 71 , 81 close to and directed against the place to be de-iced in such a way that a concentration of the air flow is obtained. The outlet openings 71 , 81 are suitably in the shape of nozzles.

The areas important to keep free from snow and ice are to be find on points and stock-rails, in the space between the point and the stock-rail, on the glide plates at the switch points, between support scotch and point, around pull rods and check rods for switch drives, around point check contacts, around arms between the points, on crossings and check rails and along the rails for a distant of some or a few ten metres in front of the switch points. Thus the allocation conduits 7, 8 ought to have their respective exhaust openings 71 , 81 directed onto the enumerated areas. Thus the distribution conduit 6 of the de-icing device will have a length of about 15 m. The allocation conduits 7, 8 are connected to each side with a c/c distance of about 30 cm. The number of allocations conduits is about 50 on each side.

Fig. 5 shows a view in perspective of a part of the distribution conduit 6 and illustrates how it can be composed of a number of modules 60a, 60b, 60c joined by easy connectable and detachable snap-in fasteners 67a, 67b, 67c. The modules can have equal length and be identical or can be of different lengths and design. For instance some of the modules can be equipped with a heater mat of the type described above.

Fig. 6 illustrates an allocation conduit 7a connected to the distribution conduit 6 and the outward part 72a of the allocation conduit 7a is angled such that it goes in the length direction with an exhaust opening 71 a pointing in the length direction. It exhausts air into the area between the stock-rail 1 a and the point 3a, such that the air flows in the channel space formed between them.

In Figs. 7 and 8 an example is illustrated having only one distribution conduit 106 with a single channel 163 only. The distribution conduit 106 is equipped with allocation conduits 107 on one side only for air exhausting towards only that side of the rail 101 a of the switch. Also in this example the distribution conduit 106 is equipped with an isolation layer 162 and of course it can be equipped with a heater mat as illustrated in the first example.

The distribution conduit 106 is situated more close to the rail 101 a towards which air is to be exhausted than the other rail 101 b. Also in this case it can be situated along the centre line.

The example illustrated in Figs. 7 and 8 is particularly suitable when one needs to exhaust heated air towards one side of the switch only, which is most common.

In Fig. 9 air exhaustion towards glide plates 10 is illustrated. The allocation conduits 107 connected to the distribution conduit 106 exhausts the air towards the glide plates 10 through a respective exhaust opening 171 . Each exhaust opening 171 is arranged at an outside part 172 of the allocation conduit 107, said outside part goes in the length direction and is designed as a nozzle.

In a similar way it is illustrated in Fig. 10 how the air from the exhaust openings 171 is directed onto support scotches 1 1 .

Figs. 1 1 and 12 show in a survey an example of how the device can be installed at a switch. The air from the service house 40 is conducted through its outlet conduit 47 and conduits 51 to a respective supply conduit 5 being connected to a respective distribution conduit 6 for further allocation as described more in detail above.

Claims

1 . A de-icing device for removing of snow and ice from railway switches, the device includes air treatment means having pressurizing means (45) and conduit means (5, 6, 7, 8) for conduction of the pressurized air to selected areas of the switch, characterized in that the air treatment means also includes drying means (42) for drying the air and heating means (49) for heating the air, whereby the air treatment means is connected to a supply conduit means (5), the supply conduit means (5) being connected to a distribution conduit means (6, 106) and the distribution conduit means (6, 106) being connected to the allocation conduit means (7, 8, 107) connected to an exhaust conduit opening (71 , 81 ), whereby the distribution conduit supply means (6, 106) is arranged between the switch related rails and proceeds mainly in parallel therewith, whereby

the allocation conduit means (7, 8, 107) includes a number of allocation conduits (7, 8, 107), each one provided with at least one exhaust opening (71 , 81 ), and whereby

the exhaust opening (71 , 81 ) is arranged to be directed onto a respective selected area, those areas including glide plates, support cleats and the space between the point and the stock-rail.

2. A de-icing device according to claim 4 or 5, characterized in that the allocation conduit means (7, 8, 107) includes allocation conduits (7, 8, 107) describing an angle of 45 to 90 degrees in relation to the distribution conduit supply means (6), preferably 80 to 90 degrees..

3. A de-icing device according to any of the claims 4 - 6, characterized in that the allocation conduits (7, 8) include such allocation conduits (7, 8) which start from opposite sides of the distribution conduit means (6).

4. A de-icing device according to any of the claims 3 - 7, characterized in that the distribution conduit means (6) has a width being 1 .5 to 10 times as large as its height.

5. A de-icing device according to any of the claims 3 - 8, characterized in that the distribution conduit means (6) includes only one distribution conduit (6, 106).

6. A de-icing device according to claim 9, characterized in that the distribution conduit (106) has a single longitudinal channel (163) for the air distribution.

7. A de-icing device according to claim 9, characterized in that the distribution conduit means (6) is equipped with an inner longitudinal vertical wall (66) separating the distribution conduit (6) in two parallel channels (63a, 63b).

8. A de-icing device according to any of the claims 9 - 1 1 , characterized in that the distribution conduit (6, 106) mainly has a rectangular shape.

9. A de-icing device according to any of the claims 3 - 12, characterized in that the supply conduit means (5) and/or the distribution conduit means (6) includes outside walls (61 ) having a layer (62, 162) of isolating material at the inside thereof.

10. A de-icing device according to any of the claims 3 - 13, characterized in that the distribution conduit means (6) includes air heating elements (64a, 64b), preferably electric heating elements.

1 1 . A de-icing device according to claim 14, characterized in that each heating element (64a, 64b) is in form of a lining arranged on the inside of each one of the conduit walls.

12. A de-icing device according to any of the claims 3 - 15, characterized in that each one of the distribution conduits of the distribution conduit means (6) is made up of elongated modules (60a, 60b, 60c), said modules being arranged to be connected with each other and loosened from each other in situ.

13. A de-icing device according to any of the claims 3 - 16, characterized in that the allocation conduit means (7, 8) includes at least an allocation conduit (7a), the part (72a) of which closest to the exhaust opening (71 a) proceeds in another direction than the rest of the allocation conduit, preferably in parallel with the rails of the switch.

14. A de-icing device according to any of the claims 1 - 17, characterized in that the conduit means is housing components (68) to be used for other service functions than air exhausting.

15. A method for removing of snow and ice from railway switches, where air is exhausted onto selected areas of the switch, characterized in that the air to be exhausted is dried and said method is carried out by a de-icing device according to any of the claims 1 - 18.