EP3141657A1

EP3141657A1 - Rail switch heating device

Info

Publication number: EP3141657A1
Application number: EP15002631.8A
Authority: EP
Inventors: Andrzej Cholewa
Original assignee: Track Tec SA; Track Tec S A
Current assignee: Track Tec SA; Track Tec S A
Priority date: 2015-09-09
Filing date: 2015-09-09
Publication date: 2017-03-15
Anticipated expiration: 2035-09-09
Also published as: SI3141657T1; RS57507B1; LT3141657T; EP3141657B1; HUE039579T2; PL3141657T3; DK3141657T3

Abstract

A device for heating rail switches as consisting of a sliding plate (1) with the upper part (3) with a sliding surface (9) and of a base plate (2) fitted with an induction heater (12) consisting of an inductor (4) and a winding placed inside the sliding plate (1) connected to a power source. The induction heater (12) has a shape similar to a cylinder with an annular hollow (5) where a coil spool (6) is placed as mounted on an inductor pin (10) and the induction heater (12) is located inside a hollow (11) in the sliding plate (1).

Description

The subject matter of the invention is a device intended for heating rail switches with the use of an inductive excitation element.
Devices for heating railway switches by means of induction heaters are known in practice. In general, their operation consists in placing in the vicinity of one of elements of the railway switch an induction coil energised with current from the contact line. The coil generates a magnetic field exciting eddy currents inside switch elements as they are made basically of ferromagnetic materials. Under the impact of the eddy currents, heat is generated that warms individual fragments of the railway switch and prevents moving parts from being immobilised as a result of adverse weather conditions, including icing and snow.
Such a solution is known for example from the description of European patent No EP2720513 (B1 ) where a device for heating rail switches has been revealed as fitted with rail with an AC generator that supplies an inductor comprised of inductive coil. The inductor is attached to the main rail or to the switch rail. In this solution, the device is additionally fitted with a control module that controls the intensity and frequency of the current feeding the inductor.
In the U.S. Patent No. US6664521 (B1 ), a solution has been revealed for defrosting components of rail switches, including primarily a sliding plate as an element of the switch with the switch-point rail travelling on the element surface. In this solution, the sliding plate is heated by means of an inductive coil wrapped around the sliding plate base. The coil is shaped like an elongated duct and is connected by a cable with a transformer supplying the heating module with high-frequency current.
In both the above solutions, the heating module in the form of an induction heater is placed outside the sliding plate, which exposes it to mechanical damage and harmful atmospheric conditions.
The Japanese patent application JP2001131901 (A ) presents a device for heating rail switches through generating magnetic induction in the vicinity of the spot that requires heating. In this solution, the induction heater is made of coils consisting of a hollow core on which conductor coils are wound, as arranged longitudinally, thus creating a plate connected to a generator. The so created inductive heater is inserted in hole inside a sliding plate and adjoins the upper surface of the plate inside the hole. The heater produces eddy currents in the sliding plate, thus raising its temperature and melting the snow and ice accumulating on the surface of the plate.
The above solution represents the technical level most similar to the solution being the it subject matter of this invention. Although the heater is protected against adverse weather conditions, its structure is, which makes the heater exposed to damage. Moreover, mounting of the heater inside the sliding plate requires sealing of the outer part of the sliding plate hole so that to insulate inductive coils from outer conditions. At the same time, the hole hollowed out inside the plate weakens the plate structure and makes it more vulnerable to damage.
The device for heating rail switches by this innovation consists of an induction heater in the shape of a cylinder, or a solid body resembling a cylinder in shape, made of ferromagnetic material and constituting the core of the inductor, with an annular hollow inside the heater. As a result, the cross section of the inductor core is similar to the letter "E" in shape. On the inductor core situated inside the cylinder, there is a spool with a conductor wound. The conductor is connected to a power generator conveniently supplied with current from the traction through a system of e.g. inverters adjusting the voltage level, especially in the case of direct current electric tractions. The so shaped cylindrical induction heater is placed inside the sliding plate between its base and the upper part with the switch point travelling on it. The cylindrical heater is set in a hollow with a circular cross-section, as fitted to the heater size and located in the upper part of the sliding plate fixed on the heater. An analogous hole with the shape fitted to the induction heater cross-section can be located in the plate base. In this preferable solution variant, the induction heater is partially inserted in the hole in the plate base whereas the upper part of the plate is fixed on the part of the induction heater which protrudes above the plate base surface. Both the hole on the plate base and the one in the upper part of the plate are close-fitted to the heater size.
In the preferable variant of the solution, there is a central hole situated in the central part of the heater with a pin fixing both the heater and the upper part of the sliding plate to the base. In the hollow in the sliding plate, there is a central stem with a through hole.
The solution based on the invention creates a structure where the heating element is located inside the sliding plate, which provide support to its upper part and favourably affects the durability and rigidity of this element of the rail switch. The heater size can be relatively large in relation to the whole plate since after mounting, the plate base, the heater inductor cylinder, and upper part of the sliding plate make a uniform and stable structure. The cylindrical shape of the heater with the coil drawn in the core inside the heater ensures a favourable magnetic flux distribution. According to the invention described, the induction heater functions on the similar principle as other such type solutions by generating eddy currents in the sliding plate and thereby raises the temperature of the rail switch element crossover thus melting the icing and snow retained on the surface. With the heater configuration conformable with the invention, magnetic flux propagates crosswise to the plate surface, which increases the amount of heat induced, as compared with other known solutions, with the same amount of electricity fed to the heater.
Compared to the JP2001131901 solution (A), the solution in question allows to avoid the adverse phenomenon of mutual induction caused by mutual penetration of magnetic fields of individual coils arranged in parallel.
The subject matter of the invention in the favourable design option is shown the drawing where fig. 1 shows the top view of the sliding plate with a visible AC power supply source; fig. 2 shows the longitudinal section of the plate with a visible base, the induction heater with bolting and the upper part of the sliding plate; fig. 3 shows the sliding plate cross-section; fig. 4 shows the inductor core cross-section; fig. 5 shows the spool with the winding applied in the dimetric projection; fig. 6 shows an assembled heater consisting of the inductor core with the coil spool put on the inner pin; whereas fig. 7 is a reference drawing showing on one side sliding plates fixed to a sleeper without visible rails and, on the other side, an exposed main rail and the switch point resting on sliding panels, and fig. 8 shows the upper part of the plate in a perspective view, where there is a hollow with a circular section with the central pin with a through hole.
Designations used in the figures are explained below:

1 - sliding plate, 2 - plate base, 3 - upper part of the plate, 4 - inductor core, 5 - annular hollow, 6 - coil spool, 7 - central hole, 8 - fixing pin, 9 - sliding surface, 10 - inductor pin, 11 - hollow with a circular section, 12 - induction heater, 13 - main rail, 14 - switch point, 15 - central stem.

In this example of the invention design, the rail switch heating device consists of sliding plate 1 as made of base plate 2 with a hollow with a circular cross-section and plate upper part 3 also fitted circular cross-sectioned hollow 11, and, additionally, of induction heater 12, which in turn consists of inductor core 4, as made of a ferromagnetic material, with annular hollow 5 and inner inductor pin 10. As a result, inductor core 4 is in the shape of letter "E". inside annular hollow 5, there is coil spool 6 put on inductor core 10 with a winding of conductive wire applied on the spool. Inductor core 4 with coil spool 6 placed inside the core make together induction heater 12 placed inside sliding plate 1 in the hollow in base 2 of sliding plate 1. On heater 12, plate upper part 3 is mounted. The part is provided with hollow 11 with a circular cross-section; the hollow inner diameter corresponds to the outer diameter of induction heater 12. Hollow 11 has central stem 15 with a through hole with the diameter corresponding to that of central hole 7. The heater can be pressed into hollow 11 or inserted with a slight clearance. Once plate upper part 3 is put on induction heater 12, it adheres closely to plate base 2, while induction heater 12 fills basically the entire space inside hole in base plate 2 and inside hollow 11, forming together with plate base 2 and plate upper part 3 a relatively uniform whole with plate upper part 3 adhering closely to both plate base 2 and to the upper surface of induction heater 12. in this way, the sliding plate 1 provides stable support for switch point 14 travelling on sliding surface 9. In the presented example of the preferred option of the invention, both induction heater 12 and plate upper part 3 are bolted to plate base 2 with mounting pin 8 placed inside central hole 7 which runs through the middle of induction heater 12 and at the same time forms the hollow in the upper part of plate 3 and plate base 2. Induction heater 12, when connected to the power supply winding, generates a magnetic field that induces eddy currents in sliding plate 1, which results in heating the plate and melting the ice and snow deposited on rail switch elements, particularly on sliding surface 9 of sliding plate 1. In the preferable variant shown in the design example, the magnetic flux is essentially perpendicular to the plane of sliding surface 9, thus providing heating of the whole of sliding surface 9, which is particularly important since it allows switch point 14 to move freely on sliding surface 9. In the preferable design example, the device based on the invention is supplied with the railway traction current with the use of an AC generator with 10-100 kHz frequency current fed to the winding. It has been proved in tests that the most effective heating of the sliding plate is obtained at the above frequency range.
The solution based on the invention can be used in most of rail switches applied in the railways and practically for each type of sleepers.

Claims

Device for heating rail switches consisting of a sliding plate with the upper part provided with a sliding surface and of the plate base, fitted with an induction heater consisting of an inductor an a winding, placed inside the sliding plate and connected to a power supply source, distinctive by the fact that the induction heater (12) is similar in shape to a cylinder with an internal annular hollow (5) where a coil spool (6) is placed as mounted on an inductor pin (10) and the induction heater (12) is placed inside the hollow (11) in the sliding plate (1).
Device for heating rail switches as per claim 1, distinctive by the fact that the hollow (11) is provided with a central stem 15 with a through-hole with the diameter corresponding to that of the central hole 7
Device for heating rail switches as per claim 1 or 2, distinctive by the fact that the lower part of the induction heater (12) is placed in a hole in the plate base (2) whereas the inductor core (4) has a central hole (7) in its central where a fixing pin (8) is placed which fastens the induction heater (12) to the plate base (2) and at the same time, the fixing pin (8) is connected with the upper part of the plate (3).
Device for heating rail switches as per any of the above claims, distinctive by the fact that the induction heater (12) is a solid in the shape of a cylinder in its outer outline.
Device for heating rail switches as per any of the above claims, distinctive by the fact that the symmetry axis of the inductor pin (10) is basically perpendicular to the plane where the sliding surface is located (9).
Device for heating rail switches as per any of the above claims, distinctive by the fact that the induction heater (12) is powered by the alternating current with a frequency of 10-100 kHz, generated in the generator system connected to the railway traction.