EP3075907A1

EP3075907A1 - Heating apparatus for railway switches

Info

Publication number: EP3075907A1
Application number: EP16163460.5A
Authority: EP
Inventors: Thomas Arts
Original assignee: VolkerRail Nederland BV
Current assignee: VolkerRail Nederland BV
Priority date: 2015-04-01
Filing date: 2016-03-31
Publication date: 2016-10-05
Also published as: NL2016514B1; NL2016514A; NL2021274B1; NL2021274A

Abstract

Switch heating with a to a source of galvanic current connected galvanic heating ribbon, which ribbon is located in a rigid metal profile, e.g. comprising a the ribbon containing tube, and this profile is mounted to the rail. The ribbon and/or profile are prefab; and/or the ribbon is loose or free within the profile. The profile has two tubes with mutual spacing and the tubes are mutually connected by a web plate to e.g. heat the head and foot of the rail.

Description

Switch heating with coated electrical strap in metal profile, mounted by already present bolts projecting through clamping brackets.
The invention relates to electrical switch heating for train, tram or metro, for passenger and freight transport, preferably with an overhead contact line over the railway for the power supply of the train locomotive.
WO10/142720 discloses a prior art switch heating. The electric heating ribbon comprises one or more of: one or two spiral or helical resistance wires; placed in a thin-walled, closed box profile of metal, such as steel or stainless steel (e.g., Titanium strengthened); the box section completely filled with form free galvanic insulating material, such as with powder of, for example, magnesium oxide so that the spirals mutually and to the tube profile keep a distance. If the spirals of the thus completed ribbon be connected to a galvanic power source the coils heat up by the through it flowing current and through the magnesium oxide they provide their heat to the box-shaped profile that it delivers it to the environment.
The inventor has invented one or more of the following:

1. to improve the heating effect of the ribbon by locating the ribbon in a substantially form-retaining or rigid metal profile and to mount this profile to the rail;
2. the mounting of a heating profile (for electric or fluid heating) to the rail can be improved, using clamps horizontally oriented and / or by using existing means for mounting for an already present switch component;
3. the heating effect of the ribbon can be improved by coating it with a coating of organic or mineral material, preferably a prefabricated foil.

Regarding invention 1 (ribbon in profile):

From practice it is known that this ribbon, optionally enveloped by a curable with resin impregnated fiberglass braid, is directly placed against a to be heated part of a rail and mount it by clamps with regular spacing along its length.
Preferably, one or more of the following is applicable to invention 1: prefabricated profile,. prefabricated ribbon; aluminum profile; profile comprises a thin-walled tube with preferably closed cross-section; profile contains two tubes with inter-space between; tubes are mutually connected via a web plate; flexural rigidity tube or profile at least 50% or 100% higher than that of ribbon; inside cross-sectional profile or tube is sufficiently tight fitting to allow damage free insertion of the ribbon; length profile or tube at least 2 meters; profile suitable for UIC60 or UIC54 or MP46 type of rail; profile or sleeve not covered with a layer of heat insulation.
To the advantage of the invention 1 belong to one or more of: the aluminum surface of the profile radiates less heat in comparison with the surface of the ribbon (radiant heat), making the profile to bring more heat through contact to the rail (contact heat); the profile has over the lifetime of the switch heating a good shape retention whereby the thermal contact with the rail is ensured (the ribbon suffers more from expansion and contraction due to temperature variation such that over time it deflects from the rail) ; the profile protects the ribbon from the weather and mechanical damage.

Regarding invention 2 (clamping brackets):

For example NL1022069C1 (Movares / Icesolution) discloses that a heating profile is directly mounted to the rail by inserting bolts into the web (also called: the soul) of the rail; the bolt holes in the heating profile have a tight fit. WO013/037635 (Triples) discloses a by clamping onto the rail foot-mounted clamping bracket which keeps the heating profile pressed against the web of the rail, therefore the rail remains intact.
Preferably, one or more of the following is applicable to invention 2: The profile contains a large hole that preferably receives the base of the clamping bracket with large play and permits this base to directly bear against the rail, preferably the web thereof; the clamping bracket has a base for, preferably directly bearing against the rail; to the base connects at the one or both opposite sides a wing; the base contains a bolt hole or hole for an alternative mounting means; a wing extends inclined away from the base and remote from the base it extends in opposite direction; a wing has two or three an angle with each other enclosing parts (which preferably directly connect to one another) and / or the wing makes with the base an angle; the clamping bracket is of spring steel; the clamping bracket is mounted with a fastener, such as bolt, which was already presen for the mounting of a switch part, such as a slide chair or tongue support; the clamping bracket is mounted by disassembly of a fastener present at the switch, such as bolt, then placing the clamping bracket and then again mounting of the original fastener or a similar or substitute mounting means, for example, the original fastener with modification; the base of the clamping bracket bears on a part of a, preferably detachable, switch component, such as tongue support, which switch part for example, extends through the hole in the profile, and bears directly against the rail soul; the one or more tubes extend behind the switch part, optionally included in a recess made in the switch part; the switch component is removed, then the profile is installed, then the switch component is placed back, the nor before the clamp is placed, then switch part and clamping bracket are fixed, possibly together with the fixing means of the switch component.
To the advantage of invention 2 belong one or more of: for the profile there is setting freedom for inevitable expansion and contraction by the temperature fluctuations (during heating the profile can reach 200 degrees Celsius or higher, disabled heating minus 15 degrees Celsius or colder); the profile is pressed over a great length by the clamp since the clamp extends in the length of the profile; the clamps are cheap; the assembly is reliable; there is little heat loss via the mounting bolt because the heat flow from the profile must flow through the clamping bracket to the mounting bolt and the clamping bracket is thin and has little contact locations with the profile; the clamping bracket is small dimensioned so little material use; fastening means already present at the switch for an existing switch component are used.

Regarding invention 3 (coating arond ribbon):

Graybar (United Kingdom) disclosed a ribbon that is enveloped by a curable plastic material impregnated fiberglass braid. This ribbon must via a transformer be connected to the galvanic power supply.
The metal jacket of the ribbon according to invention 3 is enveloped by a coating (e.g., foil), for which one or more of the following applies: organic and/or mineral material, such as poly-imide or mica; indeed or not adhesive film; applied in strips; indeed or not glued the jacket; in a single layer or in at least or exactly one, two, three or four layers onto each other; in strips spirally or helically wound, optionally renversé, or two, three or more strips in longitudinal direction next to each other; wound under bias; only the beginning and the end of the wound strip fixed, e.g. by adhesion; an edge overlap of the adjacent strips; edge overlap at least 1 or 5 and / or up to 15 or 30 mm; edge overlap at least 10 or 20% and / or up to 60 or 75% of the strip width, for example about 50%; film thickness, for example of a single layer of foil, at least 0.001 or 0.01 or 0.1 millimeter, and / or up to 0.5 or 1.0 millimeter.
For the coated ribbon (invention 3) preferably one or more of the following applies: directly mounted against the metal of the rail; by along its length spaced mounting means, such as clamping means, for example clamp brackets, either directly or indirectly mounted to the rail; about its substantially entire length placed in a prefabricated thin-walled tube with preferably closed profile, which tube has preferably sealed ends to be gas and/or liquid tight; the tube is made of metal, such as aluminum and/or, preferably integral, part of a with two such tubes, each having a ribbon, equipped heating profile; the tube or the heating profile is, preferably directly, mounted against the metal of the rail; the inner space of the tube contains, in addition to the ribbon, nothing other than a gas, and/or a liquid; without the intervention of a transformer the resistance wires are connected to the galvanic power supply; the one end of the ribbon is located loosely in the tube, ending at preferably a distance from the associated sealed end of the tube; at least the out of the other end of the ribbon projecting galvanic connection wires, and possibly also one or more other parts of the ribbon, project in sealed manner through the associated end of the tube; an end of the ribbon, preferably, from which the galvanic connecting wires project, is fixed with the tube, for example, the outside the tube protruding part of the ribbon is fixed with the tube; the inside the tube present ribbon part is over substantially its entire length loose in the tube.
To the advantage of the invention 3 belong one or more of: better transfer of heat to the rail presumably because the coating provides an increase of the number of contact points with the object to be heated, in that the coating provides an uneven or irregular surface the ribbon, in particular, upon application of a foil whereby the places of overlap create a marked thickening; better transfer of heat to the rail because the cover layer ensures that the ribbon radiates less heat to the environment (radiant heat) and at the same time transfers more heat through contact (contact heat); a guaranteed lifetime of 15 years.
Switch heating with one or more of: the ribbon is in a substantially form-retaining metal profile placed and this profile is mounted on the rail; the assembly of a heating profile (for electric or liquid heating) by horizontally oriented clamps and / or mounting means present for an already present switch component; the ribbon is covered with coating of organic or mineral material, preferably a prefabricated foil.
Further explanation of the invention on the basis of the drawing, without being limiting to the invention.

Fig. 1: against freezing heated switch of a railway;
Fig. 2 + 3: edge overlap spiral wound, invention 3;
Fig. 4: renversé wrapped with overlapping, invention 3;
Fig. 5: 1-wing clamp of invention 2;
Fig. 6 + 7: top and side view of FIG. 5;
Fig. 8: 2-wing clamp of invention 2;
Fig. 9 + 10: top and side view of Figure 8;.
Fig. 11 rail with invention 2;
Fig. 12, the cross-sectional view along line A-A in Fig. 11;
Fig. 13 an alternative according to invention 1;
Fig. 14: a detail;
Fig. 15: a graph;
Fig. 16: one piece of a switch;
Fig. 17: a photograph of a mounted clamp bracket;
Fig. 18: a photograph of a disassembled tongue support.

Fig. 2-4 show examples of wrapping a core with a ribbon. Fig. 5-7 and 8-10 show clamps. Fig. 6 + 7: dimensions in millimeters.
Fig. 11 shows the assembly with 2-wing clamp according to invention 2 of ribbon included in aluminum profile according to invention 1. The base of the clamping bracket bears directly against the web of the rail, for which in the aluminum profile a (preferably rectangular or equal to the shape of the base) hole is made in which the base with ample clearance fits so that the aluminum profile can expand and shrink freely without the hole edge coming against the stationary base.
Fig. 13 shows an alternative aluminum profile according to invention. 1 with two ribbons, assembled according to invention. 2. The aluminum profile comprises three tubes above each other of which the lower and the upper contain a ribbon and the side wall of the middle tube contains openings for locating and tightening the clamping brackets. This profile can be used for two types of rail by custom design of his one and the other side.
Fig. 14 shows a detail in cross section of a coated ribbon (invention 3) in aluminum profile (invention 1).
Fig. 15 shows a graph for invention 3: the on the outside of the ribbon measured temperature (measured at the exterior of the coating) rapidly increases, and the switch is sooner thawed wherein the temperature of the ribbon remains lower, therefore lower energy consumption and a lighter temperature load for the ribbon. Combined with invention 1 (ribbon in aluminum profile) energy consumption and reduced temperature stress are better.
Fig. 16 shows a switch part with tongue support at the location of the sleepers.
Fig. 17 shows how the base of the clamping bracket is supported by the mounting tab of the tongue support. In the aluminum profile in which the ribbons, between the two tubes a large rectangular hole is created. The base of the support tongue protrudes through this hole and bears directly against the rail soul, as usual. The tubes extend behind the tongue support, for which the base of the tongue support may have two recesses to to provide space to the tubes. The aluminum profile is installed by disassembly of the support tongue, then placing the aluminum profile, then putting back of the support tongue, then placing the clamping bracket, and finally inserting the bolt through the clamp and the tongue support and the rail soul and screw with the nut. The base of the clamping bracket is thus at a distance from the aluminum profile and bears, through the base of the tongue, against the rail soul.
Fig. 18 shows a disassembled tongue support seen against the against the rail soul bearing base with above and below arranged recess in which the tubes of the aluminum profile exactly fit.
The measures disclosed herein may individually in any other conceivable combination and permutation be combined in order to provide an alternative to the invention.

Claims

Switch heating with a to a galvanic current source connected galvanic heating ribbon, said ribbon is located in an substantially rigid metal profile, e.g. a the ribbon containing tube comprising, and this profile is mounted to the rail.
Heating according to claim 1, the ribbon and / or the profile are prefabricated; and / or the ribbon is loose or free in the profile.
Heating according to claim 1 or 2, the profile contains two tubes with mutual interspacing and the tubes are via a web plate connected to one another in order, for example, to heat the head or the foot, respectively, of the rail.
Heating according to claim 1, 2 or 3, the inner cross-section of the profile and / or the sleeve is of sufficient tight fit to allow damage free insertion of the ribbon.
Heating according to any one of claims 1-4, the length of the profile and / or the tube is at least 2 meters; and / or the profile and / or the tube contains only the ribbon as a filler material.
Heating according to any one of claims 1-5, the profile and / or the tube is not covered with a layer of heat insulation.
Heating according to any one of claims 1-6, the profile and / or the tube extends along the length of the rail.
Heating according to any one of claims 1-7, the profile includes a hole which receives with much clearance the base of a separate clamping bracket, the base resting directly against the web of the rail, and the clamping bracket is with a through its base penetrating mounting means mounted to the rail and keeps the profile clamped against the rail
Heating according to any one of claims 1-8, the flexural stiffness of the tube and / or profile is at least 50% or 100% higher than that of the ribbon.
Heating according to any one of claims 1-9, a switch component, such as tongue support, was dismantled to make room for the profile, then the profile is placed, then the switch component is replaced, then or before the possible clamping bracket is installed, then switch part and clamping bracket are fixed, possibly together with the fixing means of the switch component.
Heating according to any one of claims 1-10, a switch part, such as tongue support, extends through a hole in the profile and bears directly or through a clamping bracket against the rail soul.
Heating according to any one of claims 1-11, the profile is mounted by a separate clamping bracket which extends parallel to the longitudinal direction of the rail; and / or the ribbon comprises an in the longitudinal direction extending, elongated resistance element, such as wire, in a casing of electrically insulating material.