DEVICE AND A METHOD FOR MELTING SNOW AND ICE OF A RAILWAY
A device for heating of railway tracks is provided. The device comprises a magnetic field generator fed with a low-frequency current. The magnetic field generator is formed by a device without a circuit returning a magnetic flux generated by the magnetic field generator. Hereby the magnetic flux can be returned via a heater. The heater is a material generating heat when placed in the magnetic field. The heater can be the railway tracks or a plate provided in conjunction with the railway tracks.
Latest STEGIA AB Patents:
The present invention relates to devices for removing snow and ice from railway tracks and in particular from rail road switches.
BACKGROUNDIn winter climates, there is a high demand to keep railway tracks free from snow and ice. The methods and devices used for removing the snow and ice range from manually removal to thawing and heating devices of different types.
For example, U.S. Pat. No. 6,664,521 describes an inductive snow melting device. The device in U.S. Pat. No. 6,664,521 removes snow by heating a floor plate using a heating coil that is fed with a high frequency current.
Today, there is a trend toward a higher use of railways for transportation of goods and people. This has led to a higher utilization of railways. This in turn has resulted in that the maximum capacity of railroads now has been reached or almost reached in many places. The railway must hence be constantly available and there is little or no time to manually remove ice or snow from the tracks or thaw them with conventional thawing devices.
Hence there exists a need for new devices providing improved performance in snow and ice removal from railway tracks.
SUMMARYIt is an object of the present invention to provide an improved methods and devices to address the problems as outlined above.
This object and others are obtained by the methods and devices as set out in the appended claims.
As has been realized by the inventor, an inductive ice-melting and snow removal device making use of a high-frequency input current such as the device described in U.S. Pat. No. 6,664,521 has great limitations. For example, the need for high frequency components in an environment in need of ice-melting and snow removal is highly unsuitable and can cause malfunction in the system. The mean-time before failure (MTBF) will also be short.
Further, high frequency components are not desired because there will be a risk of interference with other electrical devices, in particular radio frequency devices.
The present invention solves the above problems in that an inductive heating device fed with a low-frequency current is provided. Thus, by generating heat with an inductive heating device designed to operate on low-frequency current a number of advantages can be achieved.
In accordance with embodiments described herein a device for heating of railway tracks is provided. The device comprises a magnetic field generator fed with a low-frequency current. The magnetic field generator is formed by a device generating a magnetic flux without a circuit returning the magnetic flux generated by the magnetic field generator. Instead the magnetic flux is closed via some other component here termed a heater. Hereby, the magnetic flux can generate heat in the heater. The heater is a material generating heat when placed in the magnetic field from the magnetic field generator. The heater can be the railway tracks or a plate provided in conjunction with the railway tracks or some other device generating heat when placed in a magnetic field.
The use of an inductive heating device fed with a low-frequency current in accordance with some embodiments will thus provide numerous advantages over existing devices for removing snow and ice from railway tracks. The advantages include, but are not limited to an effective use of the applied power, heat generation in a well-defined area, a simple and robust design with a high MTBF, and no high frequency radio frequency interference.
The present invention will now be described in more detail by way of non-limiting examples and with reference to the accompanying drawing, in which:
The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.
In
The railway track heating device 9 in
As set out above, the heat element 3 can be supplemented by a heat spreader 2. The purpose of the heat spreader 2 is to spread the heat generated in the heat element 3 over a larger area thereby forming a larger heater in the overall device. The heat spreader 2 can be secured to the railway tracks by means of a securing device 4. In accordance with one embodiment the railway track heating device 9 is secured to the railway tracks by the securing device 4. The securing device 4 can be clamped around the bottom section of the railway tracks and also be attached to the inductive core whereby the heating device can be held in place. The magnetic field generator 1 is fed with a low frequency power via a power cable 6. To control the heat generated by the device a thermostat 5 can in accordance with some embodiments be provided that is operative to turn the power supply off and on in response to the current temperature in the heat element or a device in thermal contact with the heat element 3.
In an alternative embodiment, the thermostat can be omitted by proper dimensioning of the heat element 3. In
The magnetic field generator 1 can be formed by an arrangement having a coil driving a magnetic flux in an inductive core, but without a circuit returning the magnetic flux. Instead the heating device, such as the railway tracks or a heat element, will serve as a return for the magnetic field generated by the magnetic field generator. The railway tracks have poor properties for conducting a magnetic flux. As a result, the railway tracks will generate heat when placed as a return closing the loop for the magnetic flux.
Some different parts of the device in
In
In
In
In
In
In
In
In
In accordance with some embodiments one or more magnetic field generators are located between the sleepers of the railway track. Further, entire railway sections can be heated as one unit. Typically, the lateral heating is limited compared to vertical heating whereby the heating can be made local at locations where heating is deemed important and or desired. For example, such locations can be railway switches, which can become stuck due to ice and snow.
As set out above, the magnetic field generator can be fed via a power supply 30 with a suitable voltage and frequency. For example, the arrangement can be fed from an existing power supply. Thus, if only 16 Hz is available at the location where the arrangement is to be deployed (because the railway is operated using 16 Hz power supply), the arrangement can be designed/dimensioned to operate at this frequency. Other suitable power frequencies can be 50 Hz and 60 Hz. The heating power generated by the arrangement can be dimensioned in accordance with the heating demand. For example, the arrangement when used for a railway switch can be dimensioned to generate heating power in the range 10-500 W, other heating powers are also envisaged such as in the range of 200 W to 2000 W or even higher than 2000 W.
In accordance with some embodiments the magnetic field generator is connected to a control unit. 40. The control unit is provided to control the power fed to the magnetic field generator so that a suitable heat is generated in the railway tracks. In accordance with one embodiment the control unit is connected to a heat sensor 50 provided in conjunction with the railway tracks. The heat sensor can be a thermostat or an IR-sensor or some other suitable sensor. The power fed to the magnetic field generator is controlled by the control unit 40 in response to the output signal from the sensor 50 or other sensors or controllers. The control unit 40 can further be connected to other sensors generally designated by reference numeral 60 in
In
Claims
1. A device for melting snow and ice of a railway, the device comprising a magnetic field generator fed with a low-frequency current and adapted to generate a magnetic flux, the device further comprising a heat element located in the magnetic flux generated by the magnetic field generator generating heat when a magnetic flux goes through the heat element.
2. The device according to claim 1, wherein the temperature in the heat element is controlled by a heating sensor.
3. The device according to claim 2, wherein the heating sensor is a thermostat.
4. The device according to claim 1 wherein the frequency of the low-frequency current is the same as the frequency of the current used by trains running on the railway tracks.
5. The device according to claim 4, wherein the low-frequency current is 16, 50 or 60 Hertz.
6. The device according to claim 1 wherein the magnetic field generator comprises a core and at least one coil generating a magnetic flux in the core when fed with the low frequency current.
7. The device according to claim 6 wherein the core of the magnetic field generator is generally E shaped.
8. The device according to claim 1, wherein the temperature of the heat element is controlled by the physical properties of the heat element.
9. The device according to claim 6, wherein a plate is provided and the plate forms at least a part of the heat element.
10. The device according to claim 9, wherein the plate is located under the railway tracks.
11. The device according to claim 10, wherein the plate is located between the sleepers of the railway tracks.
12. The device according to claim 9, wherein the plate is located under the switch points of a railway switch.
13. The device according to claim 9, wherein the plate is made of aluminum.
14. The device according to claim 9, wherein the plate is provided with holes and or slits.
15. The device according to claim 9, wherein the plate is located in an area between a tongue and a support rail.
16. A method for melting snow and ice of a railway, the method comprising feeding a magnetic field generator with a low-frequency current, and generating a magnetic flux, the magnetic flux passing through a heat element located under the railway tracks and thereby generating heat in the heat element wherein the temperature of the heat element is controlled by selection of the heat element.
17. The method according to claim 16, wherein the temperature is selected by selecting one or more of the following parameters of the heat element:
- the length, width, thickness of the heat element, the geometric shape including provision of holes or slits in the heat element, selection of material and combination of materials in the heat element.
18. The method according to claim 16, wherein the heat element is formed as a plate.
Type: Application
Filed: Feb 20, 2017
Publication Date: Jan 10, 2019
Applicant: STEGIA AB (Västeräs)
Inventor: Agne FÄLLDIN (Sundsvall)
Application Number: 16/069,261