Points heating device having an integrated controller

Abstract

The invention relates to a points heating device (1) for heating and mounting on a set of points for a rail-based transport system, having a heating element (2), a connection head (3) with a housing (9) arranged on the heating element (2), a temperature sensor (4) arranged outside the connection head (3) and a connection cable (11) leading out of the connection head (3). A control unit (5) is arranged inside the housing (9) of the connection head (3) and thermally conductively connected to an inner surface (17) of the housing (9), wherein the control unit (5) has a circuit board (10) with a processor (6) and a power circuit breaker (7) for controlling the heating element (2), and wherein a heat transfer element (8) is thermally conductively mounted between the power circuit breaker (7) and the inner surface (17) of the housing (9), and wherein the connection head (3) with the inserted control unit (5) is sealed by sealing elements (12, 13).

Description

[0001] Switch heating device with integrated control

[0002] Technical area

[0003] The invention relates to a switch heating device with integrated control.

[0004] State of the art

[0005] Switch heating devices for preventing the moving parts of switches in rail-based transport systems from freezing by heating the switches are well known. For example, electric heating elements with a connection head are used on the switch rails. The electric switch heaters are usually switched on and off as needed, either manually or by a central control system. The central control system switches several switches, each with several heating elements, on or off.

[0006] Such switch heating devices are known, for example, from WO 2019 / 075248A1, WO 2020 / 053842A2, or DE102014113541A1. A disadvantage of these conventional switch heating devices with manual activation or central control is that the central control switches all heating elements connected to the control system on and off together, or in groups, without knowing the exact thermal situation of each individual heating element. The decisive factor for activation is usually the thermal situation at the most exposed switch, which leads to unnecessary power consumption because individual heating elements heat the rail to a higher temperature than necessary. Such heating systems are also prone to failure, for example if the power is too low to reach the required rail temperature.In addition, the known control elements are designed in such a way that, due to their size and nature, they cannot be mounted directly on a rail. This is the object of the invention.

[0007] The present invention is based on the object of providing a switch heating device which consumes little energy, is not susceptible to failure, enables good load management, and which is small and compact so that it can be attached to a rail in the area of ​​a switch.

[0008] Description of the invention

[0009] This task is solved by a switch heating device with an integrated control unit. The switch heating device for heating and mounting on a switch for a rail-bound transport system comprises a heating element, a connection head with a housing arranged on the heating element, a temperature sensor arranged outside the connection head, and a connecting cable leading from the connection head. A control unit is arranged within the housing of the connection head and is thermally connected to an inner surface of the housing. The control unit has a circuit board with a processor and a power switch for controlling the heating element, and a heat transfer element is thermally conductively mounted between the power switch and the inner surface of the housing. Furthermore, the connection head with the inserted control unit is completely sealed with sealing elements.

[0010] The advantage of such a switch heating device with integrated, independent control is that the device can react precisely and independently to the local thermal situation, even without a higher-level central control system. This leads to a significant reduction in energy consumption and a reduction in malfunctions. The invention enables the individual control of all heating elements without the need to lay additional cables. In the switch heating device according to the invention, each device knows its thermal situation and is able to react independently if the rail temperature exceeds or falls below a set temperature. The circuit board of the control unit preferably comprises a processor for processing the control data, which processor is preferably programmed with a set temperature.Depending on whether the setpoint is above or below the value measured by the temperature sensor, a signal is sent from the processor to the power switch and the heating element is switched on or off.

[0011] The power switch is preferably a power semiconductor. In another embodiment, the power switch can also be a relay or a power controller.

[0012] The control unit is thermally connected to an inner surface of the housing by a heat transfer element thermally connected between the circuit breaker and the inner surface of the housing. The heat transfer element is an element that transports energy in the form of heat across at least one thermodynamic system boundary and is preferably made of metal, a thermally conductive paste, a thermally conductive gel, or a thermally conductive potting compound.

[0013] The control unit is capable of communicating with a higher-level control system, preferably via control wires or a radio connection. The control unit can receive instructions from the higher-level control system and return status messages and temperature values. If the higher-level control system fails, the control unit can detect this and independently perform the control function. In addition, a higher-level control system can send the command to switch each individual point heating element on or off. This allows the load to be distributed so that not all point heating elements switch on or off at the same time. This leads to intelligent load management, in which the power is distributed among different points to prevent excessive power consumption. This, in turn, reduces the susceptibility to failure, because not all

[0014] Switch heating devices are connected to one another. The heating element is preferably an electrical heating element, particularly preferably an ohmic heating element. The heating element is, for example, a heating rod or a mineral-insulated heating element. The heating element is preferably a heating rod. Depending on its arrangement on the rail, the heating rod preferably has one or more bends and is up to 12 meters long, preferably 0.5 to 8 meters long.

[0015] The connection head of the present invention must be small enough to be mounted on a rail. Small connection heads with integrated electronics are at risk of overheating. The use and special arrangement of the heat transfer element between the circuit breaker and the inner wall of the housing makes it possible to dissipate the heat generated by the circuit breaker inside the connection head to the outside. Despite its compactness, the housing has a sufficiently large surface area to dissipate heat to the environment via convection, thermal radiation, and thermal conduction. This makes the connection head of the present invention small, compact, yet completely sealed, and can be mounted directly on a rail.

[0016] The connection head preferably has a cylindrical shape with a housing and two head ends, wherein the first head end is preferably designed as a cable gland and the second head end is preferably designed as a housing closure on the heating element side. One or more connection cables and preferably a sensor cable connected to the temperature sensor lead through the cable gland. The cable gland is preferably a cable entry with the function of a stuffing box, which offers particularly good sealing of a cable, a line or an insulated conductor as it passes through a housing wall. The heating element is guided through the housing closure. The housing closure preferably has the form of a press-in or screw-in nipple, preferably the form of a screw-in nipple, preferably soldered to the heating element, and closes the head end of the connection head on the heating element side.The casing shell of the preferably cylindrical housing preferably has an annular recess on the outside for accommodating mounting clamps for attaching the point heating device to a rail. The connection head with housing, cable gland, and housing closure is preferably made of stainless steel, preferably chromium-nickel steel. The connection head is completely sealed with sealing elements to prevent external influences such as moisture or dirt from penetrating. The cable gland is sealed with a first sealing element, preferably a compressible rubber plug with through-holes for the cables, and compression and sealing are achieved by tightening a union nut. The housing closure is sealed with a second sealing element.The second sealing element is preferably an O-ring or a flat seal, but can also be designed to be metallically sealed or liquid-tight.

[0017] The connecting cable leading from the connection head has power wires for transmitting current from a power source to the connection head with control unit and to the heating element. In a further embodiment, the connecting cable has at least one, preferably two or three additional wires, so-called control wires, for transmitting control data in order to communicate with an external higher-level control system. In a further embodiment, communication with the external higher-level control system can also take place wirelessly. If a higher-level control system is present, the higher-level control system can issue instructions to the control unit of the switch heating device according to the invention. Conversely, the control unit can return status and temperature data to the higher-level control system.For example, the higher-level controller specifies a temperature setpoint and compares this with a value measured by the local temperature sensor, thus switching the heating element on when the measured value is below the setpoint, or switching the heating element off when the measured value is above the setpoint. The external higher-level controller can be installed at a location along the tracks and control several points together. The point heating device with an integrated control unit in the connection head and external local temperature sensor is thus able to switch the heating elements on or off as needed using a predefined internal setpoint or to follow a setpoint specified by an external higher-level controller. The predefined internal setpoint can be individually programmed on the processor for each control unit.

[0018] The temperature sensor located outside the connection head is preferably connected to the control unit inside the connection head via a sensor cable. In another embodiment, the temperature sensor is connected to the control unit inside the connection head via a radio link. The temperature sensor is preferably located on a rail near the connection head, preferably less than 3.5 meters away, thus keeping the sensor cable short. This increases the robustness of the switch heating device.

[0019] Preferably, the switch heating device has a power supply, preferably an electronic power supply or a transformer, to generate the low electrical voltage.

[0020] In a preferred embodiment, a pressing element is arranged between the control unit and the inner surface of the housing in order to hold the control unit in position and to improve heat transfer. The pressing element is preferably arranged between the circuit board and the inner surface of the housing on the side of the circuit board opposite the circuit breaker. In a further embodiment, the pressing element is arranged between the circuit board and the circuit breaker. In a further embodiment, the switch heating device comprises two pressing elements, one between the circuit board and the circuit breaker and a second between the side of the circuit board opposite the circuit breaker and the inner surface of the housing. The pressing element can be flexible or rigid and made of metal, for example in the form of a spring, or of plastic.The present switch heating device is small and compact, fully sealed, can be mounted directly on a rail in the area of ​​a switch, and each heating element can control itself according to an internal or external command, thus switching itself on or off. Preferably, each switch is equipped with several switch heating devices, which are preferably attached to both the stock rail and the tongue rail. In one embodiment, for example, each tongue and stock rail of a switch has two switch heating devices each.

[0021] In addition, the present invention relates to a method for heating switches for a rail-bound transport system with a switch heating device according to the invention, wherein the control unit compares a setpoint pre-programmed in the control unit with a value measured by the temperature sensor in order to regulate the heating element or to switch it on or off.

[0022] In a further embodiment, the method comprises specifying an external setpoint value of an external higher-level controller and comparing this setpoint value with a value measured by the local temperature sensor in order to switch the heating element on or off.

[0023] Furthermore, the invention relates to the use of a switch heating device according to the invention for heating a switch for a rail-bound transport system.

[0024] Combinations of two or more of the above-listed designs and variants are conceivable and claimed.

[0025] Further advantages of the invention will become apparent from the following description, in which the invention is explained in more detail with reference to embodiments shown in the drawings.

[0026] Short description of the figures Showing:

[0027] Fig. 1 shows a switch heating device in schematic representation,

[0028] Fig. 2A a connection head in perspective view from the side,

[0029] Fig. 2B is a cross-section through the connection head of Figure 2A along the line CC,

[0030] Fig. 3A a switch heating device attached to a rail in perspective view,

[0031] Fig. 3B is a cross-section through a switch heating device shown in Figure 3A attached to a rail,

[0032] Fig. 4 is a schematic representation of a rail switch with several switch heating devices, and

[0033] Fig. 5 is a schematic representation of four switch heating devices connected to a higher-level control system.

[0034] In the figures, the same reference symbols are used for the same elements and explanations of a specific reference symbol apply to all figures unless expressly stated otherwise.

[0035] Embodiments of the invention

[0036] Figure 1 shows a schematic representation of a switch heating device 1 with a heating element 2, a connection head 3 connected to the heating element, and a temperature sensor 4, which is connected to the connection head 3 via a sensor cable 15. A connection cable 11 with several power wires (not shown) and one or more control wires (not shown) leads from the side of the connection head 3 opposite the heating element 2 and is connected to a power source and, if desired, to an external control unit.

[0037] Figure 2A shows a perspective view of the exterior of a connection head 3. The connection head 3 has a housing 9 with a cylindrical housing shell 32 and two head ends, the first head end 14 being designed as a cable gland 21 and the second head end 19 as a heating rod-side housing closure 20. The connection cable 11 leads from the cable gland 21, and the heating element 2 leads from the housing closure 20. The housing shell 32 of the cylindrical housing 9 has an annular recess 33 on the exterior for receiving fastening clamps (18, not shown).

[0038] Figure 2B shows a cross-section along the line CC through the connection head 3 of Figure 2A. The connection head 3 has a housing 9 with an inner surface 17 and a cable gland 21 at a first head end 14 and a housing closure 20 at a second head end 19. A control unit 5, comprising the printed circuit board 10, the processor 6 and the power switch 7, is arranged within the housing 9 of the connection head 3 for controlling, i.e. for switching the heating element 2 on and off. The control unit 5 has a printed circuit board 10 with a processor 6 and a power switch 7 for controlling, i.e. for switching the heating element 2 on and off. The processor 6 is soldered onto the printed circuit board 10. The power switch 7 can be designed, for example, as a power semiconductor, relay or power controller and is connected to the printed circuit board 10.A heat transfer element 8 is thermally conductively mounted between the circuit breaker 7 and the inner surface 17 of the housing 9 in order to conduct heat generated by the circuit breaker 7 from the circuit breaker 7 directly to the housing 9 of the connection head 3. The heat transfer element 8 is a metal element, a thermally conductive paste, a thermally conductive gel, or a thermally conductive potting compound, and is in contact with the inner surface 17 of the housing 9 directly or via a thermally conductive compound. A pressing element 16 is preferably arranged between the control unit 5 and the inner surface 17 of the housing 9 in order to hold the control unit 5 in position. The control unit 5 with the printed circuit board 10 and the circuit breaker 7 is either attached, for example glued, to the inner surface 17 of the housing 9 via the heat transfer element 8 and possibly a thermally conductive compound, or is pressed against the inner surface 17 of the housing 9 via a pressing element 16.

[0039] The heating element 2 extends through the housing closure 20 of the second head end 19 of the connection head 3 into the connection head 3. The heating element 2 preferably has two connection pins 23 (only one is visible here in the side view). The two connection pins 23 are electrically connected to the circuit board 10 via two cables. To hold the circuit board 10 in position, a holder element 22 is arranged on the housing closure 20. This holder element has a central recess for the connection pins 23 to pass through, so that the circuit board 10 does not rotate when the housing 9 is screwed onto the housing closure 20.

[0040] The connecting cable 11 and the sensor cable 15, both connected to the circuit board 10, pass through the cable gland 21. The sensor cable transmits data from the temperature sensor (not shown) to the control unit 5. The connecting cable 11 includes power wires (not shown) for supplying the control unit 5 with electrical power, which is switched by the power switch 7 and subsequently required to heat the heating element 2. If desired, the connecting cable 11 additionally includes one or more control wires for transmitting control data, preferably via a bus protocol, in order to communicate with a higher-level controller.

[0041] The connection head 3 with the inserted control unit 5 is completely sealed with sealing elements, preventing external influences such as moisture or dirt from penetrating. The cable gland 21 is sealed with a first sealing element 12, preferably a compressible rubber plug with through-holes for the cables. Compression and sealing are achieved by tightening a union nut. The housing closure 20 is sealed with a second sealing element 13. The second sealing element 13 is preferably an O-ring or a flat gasket, but can also be designed with a metallic seal or a liquid seal.

[0042] Figure 3A shows a rail 24 with an attached switch heating device 1. The switch heating device 1 has a connection head 3, a heating element 2 leading from the housing closure 20 of the connection head 3, preferably a heating rod with a bend, a temperature sensor 4 arranged on the rail with a sensor cable 15, and a connection cable 11. The sensor cable 15 and the connection cable 11 lead from the side of the connection head 3 opposite the housing closure 20 through the cable gland 21. The connection head 3 is attached to the rail 24 via a fastening element 25, preferably a fastening clamp 18.

[0043] Figure 3B shows a cross-section through a rail 24 and a connection head 3, as shown in Figure 3A, wherein the connection head 3 is attached to the rail 24 via the fastening element 25. The fastening element 25 comprises a fastening clamp 18.

[0044] Figure 4 shows a schematic representation of a switch with a first stock rail 26, a second stock rail 26', a first tongue rail 27, and a second tongue rail 27'. Two switch heating devices 1, T, 1" are arranged on each of the stock rails 26, 26' and the tongue rails 27, 27', each of which can switch on and off independently, depending on the rail temperature measured by the temperature sensor and the temperature setpoint specified by the control unit or a higher-level controller.It is possible, for example, that the first switch heating device 1" on the first tongue rail 27 switches off because it is in contact with the first stock rail 26 heated by the first switch heating device 1 and thus sufficient heat is available, but the first switch heating device T of the second tongue rail 27', which is not in contact with the heated second stock rail 26', switches on because the second tongue rail 27' is cooled from all sides and therefore has a higher heat requirement. It is also possible that if a switch is illuminated by the sun, less heat is required than for a neighboring switch which is in the shade. With the switch heating device of the invention, the heating elements of the sunny switch will temporarily switch off because the target temperature has been reached thanks to the solar radiation. The same applies to switches with more or less strong wind exposure.It is possible for all point heaters 1 of one point to be switched on, while those of the adjacent point are switched off. This results in significant power savings, since not all point heaters 1 are always heated. Additionally, a higher-level controller can command each individual point heater to switch on or off. This allows load distribution so that not all point heaters switch on or off at the same time.

[0045] Figure 5 shows a schematic representation of four point heating devices 1, each with a connection head 3, a heating element 2, a temperature sensor 4 with sensor cable 15, and a connection cable 11. The connection cable 11 of the four point heating devices 1 is connected to a higher-level controller 28 via a control wire. The higher-level controller 28 is connected to a weather sensor 29, a temperature sensor 30, and a rain sensor 31 and can, as required, supply control data to the control unit (5, not shown) arranged in the connection head 3 and switch the point heating device 1 on or off. In one embodiment, the control unit (5, not shown) arranged in the connection head 3 has a preprogrammed setpoint temperature and compares this value with a value measured by the respective temperature sensor 4. If the value of the temperature sensor 4 is below the preprogrammed setpoint, the heating element 2 is switched on.If the value of temperature sensor 4 exceeds the preprogrammed setpoint, heating element 2 is switched off. In another embodiment, the higher-level controller 28 can specify a temperature setpoint for the switch heating device 1, which it has calculated, for example, from weather data. The control unit 5 compares this setpoint with a value measured by the local temperature sensor 4 and automatically switches the respective heating element 2 on or off, so that the setpoint temperature on the rail is maintained.

[0046] List of reference symbols

[0047] 1 ,T, 1“ switch heating device

[0048] 2 heating elements

[0049] 3 Connection head

[0050] 4 Temperature sensor

[0051] 5 Control unit

[0052] 6 processor

[0053] 7 circuit breakers

[0054] 8 Heat transfer element

[0055] 9 housings

[0056] 10 circuit board

[0057] 11 connection cables

[0058] 12 first sealing element

[0059] 13 second sealing element

[0060] 14 first head end

[0061] 15 sensor cables

[0062] 16 Pressure element

[0063] 17 Inner surface of the housing

[0064] 18 Mounting clip

[0065] 19 second head end

[0066] 20 Housing closure

[0067] 21 Cable gland

[0068] 22 Holder element

[0069] 23 connecting pin

[0070] 24 rail

[0071] 25 Fastening element

[0072] 26, 26' stock rail

[0073] 27, 27' tongue rail

[0074] 28 Higher-level control

[0075] 29 Weather sensor

[0076] 30 Temperature sensor

[0077] 31 Rain sensor

[0078] 32 Housing shell

[0079] 33 annular depression

Claims

Patent claims 1. Switch heating device (1) for heating and attaching to a switch for a rail-bound transport system, with a heating element (2), a connection head (3) arranged on the heating element (2) with a housing (9), a temperature sensor (4) arranged outside the connection head (3) and a connection cable (11) leading from the connection head (3), characterized in that a control unit (5) is arranged within the housing (9) of the connection head (3) and is thermally conductively connected to an inner surface (17) of the housing (9), wherein the control unit (5) has a printed circuit board (10) with a processor (6) and a power switch (7) for controlling the heating element (2), and wherein a heat transfer element (8) is thermally conductively attached between the power switch (7) and the inner surface (17) of the housing (9), and wherein the connection head (3) with the control unit (5) inserted is provided with sealing elements (12, 13) is sealed.

2. Switch heating device (1) according to claim 1, characterized in that the heat transfer element (8) is made of metal, a thermally conductive paste, a thermally conductive gel or a thermally conductive casting compound and ensures the thermally conductive connection of the control unit to the housing.

3. Switch heating device (1) according to one of the preceding claims, characterized in that the connecting cable (11) has power wires for transmitting the power from a power source to the connecting head (3) and at least one control wire for transmitting control data from a higher-level control to the control unit (5).

4. Switch heating device (1) according to one of the preceding claims, characterized in that the outside of the connection head (3) arranged temperature sensor (4) is connected to the control unit (5) via a sensor cable (15). Point heating device (1) according to one of the preceding claims, characterized in that a pressing element (16) is arranged between the control unit (5) and the inner surface (17) of the housing (9) in order to hold the control unit (5) in position. Point heating device (1) according to one of the preceding claims, characterized in that the pressing element (16) is made of metal or plastic. Point heating device (1) according to one of the preceding claims, characterized in that the housing (9) is cylindrical. Method for heating points for a rail-bound transport system with a point heating device (1) according to one of claims 1 to 7, characterized in that the control unit (5) compares a setpoint preprogrammed in the control unit (5) with a value measured by the temperature sensor (4) in order to switch the heating element (2) on and off.Method for heating switches for a rail-bound transport system, using a switch heating device (1) according to one of claims 1 to 7, characterized in that the control unit (5) compares a target value specified by a higher-level controller (28) with a value measured by the temperature sensor (4) in order to switch the heating element (2) on and off. Use of a switch heating device (1) according to one of claims 1 to 7 for heating a switch for a rail-bound transport system.

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