HEATING DEVICE FOR RAILWAY TRACKS

Abstract

The present invention relates to heating device for melting snow and ice from a railway track, wherein the heating device comprises a connection plate (3), a heat element (5) attached to the connection plate, and at least one securing member (7) for securing the connection plate to the track. The securing member (7) is configured to clamp a part of the track between the securing member (7) and the connection plate. An outer portion (8) of the connection plate (3) is bent inwards so that a hook (11) is formed at an end (4a) of the connection plate for receiving a part of the track, and the hook is provided with at least one through hole (16) for receiving the at least one securing member.

Claims

1. Heating device (1a; 1b) for melting snow and ice from a railway track, wherein the heating device comprises a connection plate (3, 3′), a heat element (5) attached to the connection plate, and at least one securing member (7) for securing the connection plate to the track, and the securing member (7) is configured to clamp a part of the track between the securing member (7) and the connection plate, characterized in that an outer portion (8) of the connection plate (3) is bent inwards so that a hook (11) is formed at an end (4a) of the connection plate for receiving a part of the track, and the hook is provided with at least one through hole (16) for receiving the at least one securing member.

2. The heating device according to claim 1, wherein the connection plate (3, 3′) is solid and made in one piece.

3. The heating device according to claim 1, wherein the connection plate (3, 3′) is made of a resilient material.

4. The heating device according to claim 1, wherein the connection plate (3, 3′) is made of high-tensile steel, high-tensile aluminum, or high-tensile aluminum alloys.

5. The heating device according to claim 1, wherein the heat element (5) is arranged on the outside of the connection plate (3, 3′).

6. The heating device according to claim 1, wherein the heat element (5) is attached to a bottom surface (22) or an upper surface (24) of the connection plate (3, 3′).

7. The heating device according to claim 1, wherein the connection plate (3, 3′) comprises a first section (9;9′) that defines a first plane, and the hook comprises a second section (10;10′) that defines a second plane.

8. The heating device according to claim 7, wherein the angle (a) between the first and second planes is less than 25°.

9. The heating device according to claim 7, wherein the thickness (t2) of the first section (9;9′) of the connection plate (3) is less than 30 mm, and preferably less than 25 mm.

10. The heating device according to claim 1, wherein the other end (4b) of the connection plate (3) has a thickness of less than 40 mm.

11. The heating device according to claim 1, wherein the heat element (5) is plate shaped and the thickness (t1) of the heat element is less than 30 mm.

12. Use of the heating device according to any of the claims 1-11 for heating a railway switch including a rail (40) and a tongue (45) arranged movable relative the rail, and the connection plate (3, 3′) is arranged so that it extends between the rail and the tongue of the switch to allow snow and ice between the rail and the tongue to be melted.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The invention will now be explained more closely by the description of different embodiments of the invention and with reference to the appended figures.

[0051] FIG. 1 shows one example of a heating device according to the invention.

[0052] FIG. 2 shows a cross-section through the connection plate.

[0053] FIG. 3 shows the heating device connected to a rail of a railway track.

[0054] FIG. 4a shows a view from above of a railway switch provided with a plurality of heating devices.

[0055] FIG. 4b shows a cross-section A-A through the railway switch shown in FIG. 4a.

[0056] FIG. 5 shows another example of a heating device according to the invention.

DETAILED DESCRIPTION

[0057] FIG. 1 shows a first example of a heating device 1a for removing snow and ice from a railway track according to the invention. The heating device 1a comprises a connection plate 3 having a first end 4a and a second end 4b, a heat element 5 attached to the connection plate, and at least one securing member 7 for securing the connection plate to the track. The heat element 5 is arranged on the outside of the connection plate 3.

[0058] An outer portion 8 of the connection plate 3 is bent inwards so that a hook 11 is formed at the first end 4a of the connection plate for receiving a part of the track. The hook 11 is provided with at least one through hole 16 for receiving the at least one securing member. Preferably, the connection plate 3 is made of a resilient material. For example, the connection plate 3 is made of steel or aluminum.

[0059] The connection plate 3 comprises a first section 9, and a second section 10 that is bent inwards relative to the first section 9 so that the hook 11 is formed between the first and second sections at one end of the connection plate, wherein the hook 11 defines a space 12 with an opening 14 for receiving a part of the track. The part of the track is a part of a bottom section of the rail.

[0060] The space 12 and the opening 14 have a shape and size adapted to receive a part of a bottom section of a rail. The heat element 5 is attached to the first section 9.

[0061] The second section 10 is provided with at least one through hole 16 for receiving the at least one securing member 7. The through hole is, for example, a bore. In this example, the heating device 1a comprises two securing members 7, and the second section 10 is provided with two through holes 16 for receiving the securing members 7. However, the number of through holes and type and number of securing members can vary. In one aspect, the least one through hole 16 and the at least one securing member 7 are provided engagement elements (not shown) configured to engage to each other and by that lock the securing member 7 in a fixed position relative the connection plate 3. The engagement elements are, for example, threads.

[0062] The securing member 7 is, for example, a threaded bolt or a screw. The securing member 7 is preferably elongated. In this example, the securing members 7 are threaded bolts. The through holes 16 are provided with threads configured to engage with the threads on the bolts, to allow the bolts to be moved relative the first and second sections, and to lock the securing member in relation to the second section 10, when the part of the track is clamped between the first section 9 and the securing member. In this example, the securing member 7 is provided with a pointed tip 18. The pointed tip 18 makes it easier for the securing member 7 to keep the part clamped between the securing member 7 and the first section 9 when there are vibrations in the railway track, and accordingly improves the attachment of the heating device to the track.

[0063] In this example, the heat element 5 is an electric heater comprising an electric resistor. The resistor is, for example, a tubular heating element embedded in a heat conducting material. For example, the heat element 5 comprises a tubular heating element embedded in aluminum or aluminum alloy. The heat element is flat, and the thickness t1 of the heat element is less than 30 mm and preferably less than 20 mm. The heat element 5 is provided with connection elements 20 for connection of the electric resistor to an electric power source. The heat element can be removably attached to the connection plate. For example, the heat element is attached to the connection plate by means of a bolt. In this example, the heat element is attached to a bottom surface 22 of the first section 9 of the connection plate. However, in another embodiment, the heat element can be attached to an upper surface 24 of the first section 9, as shown in FIG. 5. The heat element 5 has a contact surface adapted to be in thermal contact with the connection plate.

[0064] FIG. 2 shows a cross-section through an example of the connection plate 3. The connection plate 3 is solid and made in one piece, as seen in the figure. The first and second sections 9, 10 are designed so that the first end 4a of the connection plate 3 is shaped as a hook 11. In one aspect, the hook is U-shaped. The outer portion 8 of the connection plate 3 is bent inwards so that the hook 11 is formed at the first end 4a. The first section 9 is flat and plate shaped and defines a first plane. In this example, the second section 10 is flat and plate shaped and defines a second plane. There is a curved section located between the first and second sections 9, 10. Preferably, the angle α between the first and second planes is less than 25° so that the securing member will act with a sufficient force on the part of the bottom section of the rail that is clamped between the securing member 7 and the first section 9 to keep the part in the space 12 secure heat transfer even when there are vibrations in the rail. In this example, the angle α is about 15°, However, the angle α may vary, for example, between 0-25°.

[0065] According to one aspect, the angle α between the first and second plane is larger than 5°. The angle α between the first and second planes should suitably be adapted to the angle of the bottom section of the railway tracks. Preferably, the second section 10 has an angle α in relation to the first section 9 which corresponds to the angle of the bottom section of the rail, so that the securing member 7 will be arranged perpendicular to the surface of the bottom section and allowing to improve the attachment between the railway track and the heating device. However, the shape of the bottom section of the rails varies. Thus, the angle α may vary depending on the type of bottom section. Suitably, the angle α may vary between 0° and 25°. If the upper surface of the bottom section 42 is sloping, as shown in FIG. 3, the angle α may vary between 5° and 25°.

[0066] Preferably, the connection plate 3 is made of a heat conducting material with resilient properties. For example, the connection plate is made of high-tensile steel or high-tensile aluminum, or high-tensile aluminum alloys. Such materials have a high thermal conductivity, suitable strength, and suitable resilient properties. Preferably, the thickness t2 of the first section 9 of the connection plate is less than 30 mm, and preferably less than 25 mm to facilitate insertion of the first section 9 of the connection plate underneath the rail. The thickness of the first section of the connection plate depends on the material of the connection plate due to different mechanical strength of different material. For example, a connection plate made in aluminum needs a thickness of about 20 mm to achieve enough mechanical strength, and a connection plate made in steel needs a thickness of about 10 mm to achieve enough mechanical strength.

[0067] High pressure is needed between the rail and the connecting plate to achieve necessary transfer of heat or energy between rail and connecting plate. To achieve enough contact pressure to transfer heat between rail and connecting plate, the connecting plate can, for example, be made of high-tensile steel (tensile strength >700 MPa) or high-tensile aluminum or aluminum alloys (tensile strength >350 MPa) be used, which can create spring tension between the first plane and the second plane of the connecting plate. The momentum and resulting counterforce generated by tightening of the securing member 7 create a significant pressure, preferably more than 1.5 MPa, between the connecting plate and the rail. The pressure is necessary for good heat conductivity between the connecting plate and the rail.

[0068] The term tensile strength used in the present application refers to the Yield strength, and is defined as the stress a material can withstand without permanent deformation.

[0069] Optionally, the heating device 1a comprises a stop element 26 to ensure that the clamped part of the track is not moved away from the space 12 due to vibrations in the rail. The stop element 26 is protruding from the upper surface 24 of the first section 9 at a distance from the opening 14 of the space 12. The distance between the stop element 26 and the opening 14 depends on the size of the bottom section of the rail. In this example, the stop element 26 is a ridge extending across the first section 9.

[0070] The first section 9 of the connection plate can be rectangular. For example, the connection plate is about 300×300 mm. However, the connection plate may have other shapes.

[0071] In this example, the first section 9 comprises an inner portion 28 and an outer portion 30, as shown in FIG. 2. The heat element 5 is attached to the outer portion 30 and the hook 11 is arranged at one end of the inner portion 28. For example, the heat element 5 can be arranged at one end 4b of the connection plate and the hook 11 for receiving the part of the track is arranged at the opposite end of the connection plate. The connection plate is made of a thermally conducting material and the inner portion 28 has an upper surface adapted to be in thermal contact with the bottom section of the rail. In this example, the inner portion 28 extends between the stop element 26 and the end 4a of the connection plate, and the outer portion 30 extends between the stop element 26 and the end 4b of the connection plate.

[0072] FIG. 3 shows the heating device 1a connected to a railway track. The railway track comprises a rail 40 having a bottom section 42. The lower part of the rail is arranged between the stop element 26 and the hook 11 as shown in the figure. The first section 9 of the connection plate 3 is inserted under the bottom section 42 of the rail. The bottom section 42 is in physical contact with the upper surface 34 of the first section 9. A part of the bottom section of the rail is positioned in the space 12 between the first and second sections 9, 10. The securing member 7 is tightened so that the part of the bottom section positioned in the space 12 is clamped between the first section 9 and the tip 18 of the securing member. The second section 10 and the securing member 7 is disposed at one side of the rail, and the heat element 5 is disposed at the opposite side of the rail. Heat is transferred from the heat element 5 to the rail via the first section 9 of the connection plate.

[0073] FIG. 4a shows a view from above of a part of a railway switch comprising a plurality of heating devices 1a arranged along the switch. FIG. 4b shows a cross-section A-A through the railway switch shown in FIG. 4a. The railway switch comprises two parallel rails 40, but only one of the rails 40 is shown in the figures. As seen from the figures, the lower part 42 of the rail is in physical contact with the inner portion 28 of the connection plate, and the outer portion 30 of the connection plate is protruding from the rail towards the center of the track. The switch has tongue 45 arranged movable between the rails of the switch. The connection plate is protruding from the rail 40 towards the tongue 45 of the switch. The connection plate is arranged between the rail 40 and the tongue 45 to allow snow and ice between the rail and the tongue to be melted. The system will slowly accumulate heat in the rail by means of transfer from the heat element through the connecting plate to the rail and then on moment's notice, when ice blocks are dropped from passing trains, return the accumulated energy from the rail to the connecting plate to clear the area between the rail and a tongue of the switch by melting off lodged ice.

[0074] A method for mounting the heating device comprises inserting the other end 4b of the connection plate 3 underneath the rail 40 from outside of the track, towards the center of the railroad so that the bottom section 42 of the rail is inserted in said space 12 through said opening 14, as shown in FIG. 4 a-b, and clamping the bottom section 42 of the rail between the securing member 7 and the first section 9 of the connection plate using the second section 10 as a restraint so that the lower part 42 of the rail is in physical contact with the inner portion 28 of the connection plate, and the outer portion 30 of the connection plate is protruding from the rail towards the center of the track to allow snow and ice between the rails to be melted, as shown in FIG. 3.

[0075] FIG. 5 shows a second example of a heating device 1b according to the invention. Like or corresponding parts in the figures are indicated with like numerals. The heating device 1b differs from the previously described heating device 1a in that the heat element 5 is positioned on the upper surface of the second section 9′ of the connection plate 3′. The connection plate 3′ has a different design. The second section 9′ of the connection plate 3′ is shorter, and the second end 4b of the connection plate is provided with an upwardly protruding part to hold the heat element 5 in place as well as working as a stop element for the rail

[0076] The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims. For example, the number of securing elements can be one, two, or more than two. The shape of the hook may also vary in dependence of the shape of the bottom section of the rail.