EP1195467A2

EP1195467A2 - Point heating system

Info

Publication number: EP1195467A2
Application number: EP01308550A
Authority: EP
Inventors: Robert Atkins
Original assignee: Rail Product Design Ltd
Current assignee: Rail Product Design Ltd
Priority date: 2000-10-05
Filing date: 2001-10-05
Publication date: 2002-04-10
Also published as: EP1195467A3; GB0124004D0; GB2367580A; GB2367580B

Abstract

A points heating system for use on a railway is disclosed. Strip heaters are selectively switched on and off. In a preferred arrangement, when the heating system is switched on, a first set of heaters is maintained constantly on and further sets of heaters are cyclically switched on and off.

Description

The present invention relates to a points heating system for use on railways.
A known way of heating points involves providing a number of strip heaters adjacent the stock rail. Two temperature sensors are provided, one in the area of the toe of the points and one near the central area being heated. If the temperature sensors determine that the temperature has fallen below zero, then the heaters are turned on, and vice versa.
It is desired to provide an improved points heating system, particularly one which results in a lower overall power consumption but which is at least as effective in keeping the points operational.
According to the present invention there is provided a points heating system as claimed in claim 1.
An advantage of the present invention is that by intelligently switching on and varying which heaters are on at any particular point in time, the points can be warmed and kept above freezing point using a lower overall power consumption than conventional systems. For example, whereas a conventional points heating system may have a power consumption of 35kW for 160 mph points, the points heating system according to the preferred embodiment consumes only about 5kW in similar conditions representing a sevenfold reduction in power consumption.
Preferably, the points heating system further comprises a third set of heating elements, wherein in a first mode of operation the first and second sets of heating elements are in an ON state whilst the third set of heating elements are in an OFF state and wherein in a second mode of operation the first and third sets of heating elements are in an ON state whilst the second set of heating elements are in an OFF state.
Preferably, the points heating system further comprises a third and a fourth set of heating elements, wherein in a first mode of operation the first and second sets of heating elements are in an ON state whilst the third and fourth sets of heating elements are in an OFF state, in a second mode of operation the first and third sets of heating elements are in an ON state whilst the second and fourth sets of heating elements are in an OFF state, and wherein in a third mode of operation the first and fourth sets of heating elements are in an ON state whilst the second and third sets of heating elements are in an OFF state.
Preferably, each set of heating elements comprises two strip heaters, one being placed adjacent one rail and the other being placed adjacent another rail.
Preferably, the points heating system further comprises at least three temperature sensors, a first positioned a distance from the heating elements, a second positioned on one side of the railway line and a third positioned on the other side of the railway line.
Preferably, if either the second or third temperature sensors falls below a first temperature then the heating system is switched on.
Preferably, the first temperature is above 0°C, preferably in the range 2 and 5°C, further preferably around 5°C.
Preferably, if both the second and the third temperature sensors rise above a second temperature then the heating system is switched off.
Preferably, the second temperature is above 5°C, preferably in the range 7-9°C, further preferably around 9°C.
Preferably, if the first temperature sensor falls below 0°C but the second and third temperature sensors are above the first temperature then the heating system is switched on.
Preferably, the heating elements are positioned outside a stock rail.
Preferably, the heating elements are positioned between a switch rail and a stock rail.
Preferably, the points heating system further comprises monitoring means for monitoring for faults with the heating elements.
Preferably, the monitoring means comprises one or more solid state relays.
Preferably, the points heating system further comprises means for setting or sending an alarm upon detection of a fault.
Preferably, an alarm message is sent to a mobile phone.
Preferably, the points heating system further comprises a 4-pin plug socket for powering lighting or tools.
According to a second aspect of the present invention, there is provided a railway points heating system, comprising: a plurality of temperature sensors; a plurality of strip heaters; and control means connected to the temperature sensors, the control means operating the strip heaters, wherein when the heating system is switched on, power is supplied to a first set of the strip heaters consisting of some but not all of the strip heaters, and after a predetermined period of time power is then supplied to a second different set of the strip heaters consisting of some but not all of the strip heaters.
Preferably, during normal operation a temperature sensor must fall below a first temperature in order to switch on the heating system and two temperature sensors must reach a second higher temperature in order to switch off the heating system.
According to a third aspect of the present invention, there is provided a railway points heating system comprising: at least one temperature sensor; a plurality of heating elements; and control means for switching the heating elements on and off, wherein when it is determined to switch on the heating system, the control means switches on at least one of the heating elements and periodically switches on and off other of the heating elements.
Preferably, when the heating system is switched on, approximately 50% of the heating elements are on at any one period of time.
Preferably, when the heating system is switched on, less than approximately 75%, preferably less than approximately 67%, further preferably approximately 50% of the heating elements are on average on at any one period of time.
According to a fourth aspect of the present invention, there is provided a railway points heating system comprising: a temperature sensor; a plurality of heating elements; and a control system, wherein the control system switches some but not all of the heating elements on in a cascading manner.
According to a fifth aspect of the present invention, there is provided a method of heating points on a railway comprising: sensing a temperature; and switching on some but not all of a plurality of heating elements in a cyclical manner.
According to a sixth aspect of the present invention, there is provided a method of heating points on a railway, the points having a plurality of temperature sensors and a plurality of heating elements, wherein the method comprises the steps of: switching on some but not all of the heating elements if one of the temperature sensors detects a temperature below a first level, preferably 5°C; switching off all the heating elements only when one of the temperature sensors detects a temperature above a second level, preferably 9°C.
Various embodiments of the present will now be described, by way of example only, and with reference to the accompanying drawing in which:
Fig. 1 shows a heating system comprising eight heater elements.
A preferred embodiment of the present invention will now be described with reference to Fig. 1. When the heating system is switched on, heaters A1,A2 and C1,C2 are initially switched on and heaters B1,B2 and D1,D2 remain off.
Then after a first predetermined period of time, preferably approximately twenty minutes, heaters A1,A2 remain switched on, but heaters C1,C2 are switched off and heaters D1,D2 are instead switched on. Heaters B1,B2 remain off.
Then after a second predetermined period of time, again preferably approximately twenty minutes, heaters A1,A2 remain switched on, but heaters D1,D2 are switched off and heaters B1,B2 are switched on. Heaters C1,C2 remain switched off.
This cycle is then preferably repeated until it is determined that the heating system can be switched off.
Three temperature sensors are preferably provided, a first away from the heating strips, a second adjacent heaters A2,B2,C2,D2 and a third adjacent heaters A1,B1,C1,D1. If either the second or third sensors (i.e. the sensors adjacent the heaters) sense a temperature below a predetermined level, preferably 5°C, then the heating system is switched on.
In order for the heating system to be switched off, preferably both the second and third sensors must register a temperature above another, preferably higher, predetermined level, preferably approximately 9°C. If for some reason the first sensor registers a temperature below 0°C, but neither the second nor the third sensors have caused the heating system to turn on, then the heating system is nonetheless turned on.
Other embodiments of the present invention are contemplated which comprise four or six strip heaters instead of eight. In all cases, the heaters are preferably controlled by a trackside transformer unit.
One embodiment of the present invention comprises up to eight strip heaters, each one preferably drawing the industry standard of 200 W/m. However, according to other embodiments the strip heaters can have different power consumptions/unit length. The strip heaters are controlled by a trackside transformer unit which uses mechanical relays or solid state relays. If a relay detects a fault then a GSM alarm preferably dials a telephone number to signify an alarm. One or more thermistors may be provided which detect the temperature near the points. The strip heaters are switched on when the temperature falls below 2°C and are switched off when the temperature rises above 7°C. The system cascade cycles switching on and off the other heaters on a 20 minute per pair rotation. The system preferably has a mains failure alarm and a UPS battery backup for interrogation purposes only and will alarm dial if the mains power fails for more than twenty minutes. If an alarm occurs, the GSM will send a warning message to a mobile phone specifying which point has failed. A list of up to three mobiles can be detailed and the system will send a GSM message to notify the failure alarm to all phones. Maintenance services team currently on call at the time of the failure would preferably be the first to receive and open the GSM message and to be able to act upon it accordingly.
Another embodiment is similar to the above mentioned embodiment but further comprises a data logger which records every alarm. If interrogated this unit will detail all failures and alarms i.e. how many times a certain strip has failed, what sort of failure it was and from these details a pattern of usage and failure can be printed off for further analysis by a relevant party. Further preferably, an alarm may be sent to an allocated computer where the operator can interrogate the particular trackside transformer from which the alarm was received. In addition, the operator can check the temperature on the rail and if required turn the system on or off from the remote location.
Preferably, the trackside transformer has a 4-pin plug which can be used for lighting, kango hammers etc.
Another embodiment uses solid state relays and alarms daisy chained together. If a relay detects a fault the GSM dials a number to signify an alarm. This embodiment comprises one or more thermistors which detect the temperature near the points. It preferably switches on the toe relays below 2°C and off at 7°C. Preferably, it cycles through the other heaters on a five minute cycle.
Mechanical relays may be used in preference to solid state relays. Preferably, a test mode is provided which allows each heater to be turned on for 1 second for on-site fault finding. Preferably, a mains failure alarm and a battery backup are provided, and will dial if the mains fails for more than twenty minutes. It will preferably dial two or more numbers to signify an alarm.
A yet further embodiment is similar to the preceding embodiment but has diagnostics added so that it can detect which heater has failed. Preferably, it can be sent a message to switch on certain heaters or other remote control features, or send back status messages. It could also test the heaters every few weeks. The points heating system is also preferably operable in conjunction with a rails map display which enables which points are faulty to be highlighted.

Claims

A points heating system for a railway, comprising:

a first set of heating elements;

a second different set of heating elements;

at least one temperature sensor; and

control means for controlling said first and second set of heating elements and being responsive to said at least one temperature sensor, wherein in a mode of operation said first set of heating elements are in an ON state whilst said second set of heating elements are in an OFF state.
A points heating system for a railway as claimed in claim 1, comprising a third set of heating elements, wherein in a first mode of operation said first and second sets of heating elements are in an ON state whilst said third set of heating elements are in an OFF state and wherein in a second mode of operation said first and third sets of heating elements are in an ON state whilst said second set of heating elements are in an OFF state.
A points heating system for a railway as claimed in claim 1, comprising a third and a fourth set of heating elements, wherein in a first mode of operation said first and second sets of heating elements are in an ON state whilst said third and fourth sets of heating elements are in an OFF state, in a second mode of operation said first and third sets of heating elements are in an ON state whilst said second and fourth sets of heating elements are in an OFF state, and wherein in a third mode of operation said first and fourth sets of heating elements are in an ON state whilst said second and third sets of heating elements are in an OFF state.
A points heating system as claimed in claim 1, 2 or 3, wherein each set of heating elements comprises two strip heaters, one being placed adjacent one rail and the other being placed adjacent another rail.
A points heating system as claimed in any preceding claim, further comprising at least three temperature sensors, a first positioned a distance from said heating elements, a second positioned on one side of the railway line and a third positioned on the other side of the railway line.
A points heating system as claimed in claim 5, wherein if either the second or third temperature sensors falls below a first temperature then said heating system is switched on.
A points heating system as claimed in claim 6, wherein said first temperature is above 0°C, preferably in the range 2 and 5°C, further preferably around 5°C.
A points heating system as claimed in claim 6 or 7, wherein if both the second and the third temperature sensors rise above a second temperature then said heating system is switched off.
A points heating system as claimed in claim 8, wherein said second temperature is above 5°C, preferably in the range 7-9°C, further preferably around 9°C.
A points heating system as claimed in any of claims 6-9, wherein if said first temperature sensor falls below 0°C but said second and third temperature sensors are above said first temperature then said heating system is switched on.