DK2305530T3

DK2305530T3 - Procedure for protecting the fresh water system of a vehicle against frost

Info

Publication number: DK2305530T3
Application number: DK09012495.9T
Authority: DK
Inventors: Andreas Backhaus
Original assignee: Alstom Transp Tech
Priority date: 2009-10-02
Filing date: 2009-10-02
Publication date: 2017-03-20
Also published as: EP2305530A1; RU2010139980A; PL2305530T3; RU2559178C2; EP2305530B1; LT2305530T

Description

Prior art [0001] A fresh water system is in place in rail vehicles used for transporting passengers. This supplies, for example, a washbasin and a toilet. Other loads can, of course, be connected as well to this fresh water system.

[0002] To prevent frost damage, it is known from prior art (see, for example, CH-A-21 815) that a thermostat should be provided inside the rail vehicle and the fresh water system emptied as soon as the temperature inside the vehicle falls below 5 °C, for example.

In many cases, this so-called frost monitor works very well.

[0003] An alternative way of emptying the fresh water system of a rail vehicle is for the train personnel to operate a corresponding switch or button in case of need and thus drain the fresh water system and protect it from frost damage.

[0004] What the two alternatives have in common is that they are not feasible unless sufficient electrical or pneumatic auxiliary power is available. In addition, draining the system means emptying the fresh water tank as well, with the result that there is then no more fresh water available.

Disclosure of the invention [0005] The invention is based on the problem of providing a method and a device for protecting the fresh water system against frost damage, which, even under the most unfavourable conditions, offers a higher degree of security against frost damage. At the same time, the ability of the loads connected to the fresh water system to function should, if possible, be maintained, even after the system has been drained.

[0006] This aim is achieved according to the invention by the method described in Claim 1.

[0007] By monitoring according to the invention the voltage in the electrical system in the vehicle, it can be ensured that the water pipes and water tanks are emptied at the right time - in other words, when there is still sufficient electrical energy to empty the fresh water system or the water pipes and water tanks of the vehicle. This is because the procedure cannot be carried out without electrical energy to operate, for example, one or more directional valves and/or pumps in the piping system of the rail vehicle.

[0008] Since the water pipes and water tanks of a vehicle cannot be emptied without sufficient electrical energy, monitoring according to the invention the voltage in the electrical system provides a considerably higher level of protection against frost damage for the water pipes and for tanks filled with water.

[0009] Here, it is generally assumed that a compressed air supply is present with which system components particularly threatened by frost can be blown out and thus emptied. It is, however, also possible to design the fresh water system in such a way that the procedure is feasible without compressed air.

[0010] The threshold temperature T|imit is as a rule influenced by the location where an actual temperature suitable for monitoring the fresh water is measured. The actual tern- perature could, for example, be the ambient temperature or a temperature inside the rail vehicle.

[0011] A more advantageous development of the invention provides for at least one fresh water tank being emptied when the voltage falls below a predefined limit value. This is, however, not always necessary. In many cases, it suffices to drain only the pipes and downstream water tanks, such as, for example, a grey water tank, and also the toilets, but to leave the fresh water tank full. The reason why this is possible is that the fresh water tank, when completely filled with water, has a very great heat capacity, which means that the fresh water tank only begins to freeze after a long time. In comparison with the fresh water tank, the pipes have a very much smaller heat capacity, and therefore freeze very much faster.

[0012] It is therefore efficient and expedient in a first step to empty not only the smaller volumes, such as those, for example, in the fresh water pipes, but also those in downstream tanks, such as, for example, a hot water tank, in order to prevent frost damage. Another advantage of this phased approach is to be seen in the fact that, as soon as the voltage in the electrical system of the vehicle once again exceeds the specified first limit value, the fresh water supply will be guaranteed as before, since the fresh water tank is still filled.

[0013] If the fresh water tank has been to a large extent emptied, then, naturally, the heat capacity of the remaining amount of water will be much lower, and there will, therefore, be an increased risk of freezing. However, this also means that there will be a sufficient volume of air in the fresh water tank, provided it is of a suitable design, for the tank not to burst should the fresh water freeze, but, instead, for the increase in volume of the frozen fresh water to be compensated for within the fresh water tank.

[0014] An alternative criterion for emptying the fresh water tank can be the duration of the time interval Δτ within which the voltage lies below the specified first limit value. In this way, the specific heat capacity of the water in the fresh water tank is taken into account.

[0015] This development of the method according to the invention can still be implemented even when there is only electric power still available, and no compressed air.

[0016] In an alternative procedure for protecting the water pipes and water tanks of a vehicle - particularly, of a rail vehicle - against frost damage, it is provided for a pressure in the compressed air network of the vehicle to be monitored and, when the pressure P drops below a specified second limit value, the water pipes and water tanks to be emptied, while leaving the fresh water tank or tanks closed off. This takes into account the fact that compressed air is generally required in order to empty the water pipes and the water tanks. Typically, about 150 litres of compressed air at a supply pressure of 8 to 10 bar are required to empty all of the pipes and tanks in a rail vehicle. The method according to the invention thus guarantees that all pipes and tanks will be emptied, provided there is sufficient compressed air.

[0017] Even in this case, the fresh water tank need not be drained yet. This takes into account the fact that the fresh water tank ultimately only empties itself by the gravitational force of the water contained in it, and thus no auxiliary energy in the form of compressed air is required. To empty the fresh water tank, it is necessary only to open a valve at the outlet of the fresh water tank, and this valve is, advantageously, electrically operated.

[0018] The separation according to the invention of the procedures, depending on whether the voltage in the electrical system of the vehicle or the pressure of the compressed air network in the rail vehicle is too low, makes it possible, on the one hand, to guarantee a maximum protection against frost damage and, on the other hand, to maintain the functionality of water loads for as long as possible by emptying the fresh water tank only in case of extreme necessity.

[0019] An advantageous development of the invention provides for emptying the water pipes and water tanks, opening an outlet of the grey water tank or tanks, opening an outlet of the black water tank of the toilet, flushing the toilets at least once, and blowing out the water pipes and tanks with compressed air should the water in them not fully empty automatically by force of gravity.

[0020] In addition, it can be provided for the water pipes and/or the water tanks to empty when the temperature inside the vehicle falls below 5 °C or when a corresponding switch or button is operated by the rail vehicle personnel. The method according to the invention thus guarantees the protection against frost damage which is already familiar in systems known from prior art, and supplements these systems by monitoring the voltage of the vehicle's electrical system and the pressure level in the pressure accumulator or in the compressed air network of the rail vehicle, thereby making it possible to guarantee an additional level of protection against frost damage.

[0021] The aim according to the invention is also achieved by a control device for monitoring the water in the fresh water system and/or the service water system of a rail vehicle, whereby the control device according to the invention operates according to one of the aforementioned procedures.

[0022] If the switchable directional valves take the form of aeratable directional valves, the shut-off pipe will be aerated after the directional valve or valves is or are closed. These aerated sections of the pipes can now no longer freeze and are thus effectively protected against frost damage. As a rule, these directional valves are designed such that they are normally closed.

Drawing [0023] The figures show:

Figure 1 a rail vehicle's fresh water and service water systems according to the invention, and

Figure 2 a flowchart of a method according to the invention.

Description of embodiments [0024] Figure 1 shows the fresh water supply, as well as parts of the electrical system of the vehicle and a compressed air system, in greatly simplified form and, in part, as a block diagram. Starting from a fresh water tank 1, various loads, such as a faucet 3, a toilet flushing device 5, and a water heater 7, are supplied when necessary with water from the fresh water tank 1 via water pipes 9. Below the faucet 3, a washbasin 11 and a grey water tank 13 are shown in greatly simplified form. The washbasin 11 and the grey water tank 13 are connected by an outlet pipe 15.

[0025] Beneath the toilet flush 5, shown as a black box, there is a black water tank 17 which, like the grey water tank 13, has an outlet 19. The two outlets 15 and 19 discharge into a wastewater tank, which is not shown.

[0026] The fresh water tank 1 also has an outlet 19 which can be opened or closed by means of a first directional valve 21. Under normal circumstances, this first directional valve 21 is closed.

[0027] A second directional valve 23 is provided in the water pipe 9 immediately after the outlet from the fresh water tank 1. It is possible to close the fresh water tank 1 using this second directional valve 23 when the downstream pipes 9 and loads - in particular, the water heater 7, the faucet 3, and the toilet flush 5 - are to be emptied in the way intended by the invention. In this regard, it is advantageous, in particular, for the second directional valve 23 to take the form of an aeratable directional valve, and to be normally closed.

[0028] The second directional valve 23 is closed at the same time as the tanks 7,13, 5 are emptied, so that the outlet of the fresh water tank 1 is closed, and the supply pipes 9 are aerated. The second directional valve 23 in its closed position accordingly still allows the supply or water pipe 9 to be aerated.

[0029] In the embodiment shown, the directional valves 21 and 23 take the form of electrically operated 2/2-way valves. A drain valve is provided in the water pipe 9 between the water heater 7 and the faucet 3.

[0030] A pneumatically-operated third directional valve 25 is provided at the outlet 19 of the water heater 7. It is, however, also possible for the third directional valve 25 to be electrically operated.

[0031] The three directional valves 21,23, and 25 are connected to a control device AFD via electrical or pneumatic signal lines 27, 35. In Figure 1, the electrical signal lines are given reference number 27. The pneumatic lines, which, for example, connect the pressure accumulator 35 to the pressure switch PS, are given the reference number 37.

[0032] The control device AFD is connected via signal lines (no reference number) to a thermostat 29 and a switch 31. In addition, the control device AFD is connected to a minimum voltage relay MVR which monitors the voltage of a battery 33 rated at, for example, 110 volts.

[0033] If minimum voltage relay MVR detects a voltage which is below a first limit value Ulimit,1 of, for example, 99 volts, the minimum voltage relay MVR will send a corresponding signal to the control device AFD and, as a result, the water pipes 9 and also the consumers 7, 3 and 5 will be emptied.

[0034] The minimum voltage relay MVR sends a second and different signal to the control device AFD when the voltage is lower than a second limit value Ulimit,2 or when the voltage lies below the first voltage range Unmitj for a time interval ΔΤ greater than a specified time interval ΔΤ. When this second signal is applied to the control device AFD, the first directional valve 21 will also be opened as well, and the fresh water tank 1 emptied. Emptying the fresh water tank represents for the passengers a perceptible interference in the functioning of the rail vehicle, since all water loads will then remain out of service until the fresh water tank 1 has been refilled. For this reason, the fresh water tank 1 should only be emptied when this is unavoidable.

[0035] In many situations, it is entirely sufficient simply to empty only the loads 3, 5, and 7, and also the water pipes 9, and to leave the fresh water tank 1 filled. The reasons for this are as follows:

The fresh water tank 1, when filled with water, has a very great heat capacity, and it takes a correspondingly long time before the water in the fresh water tank 1 freezes. The water pipes 9 start to freeze very much earlier.

[0036] When the fresh water tank 1 is only partially filled, the heat capacity of the water in the fresh water tank 1 will be considerably reduced. In such a case, however, there will be an air cushion in the fresh water tank 1 which can correspondingly absorb the expansion of the water when it freezes. This is, then, in particular, possible without damage to the fresh water tank 1 when the walls of the fresh water tank are, for example, extended upwards in the form of a truncated cone so that ice which has formed can slip upwards and thus do no damage to the fresh water tank.

[0037] In a manner similar to the way in which the minimum voltage relay MVR monitors the supply voltage, a pressure switch PS monitors the pressure in a compressed air accumulator 35. As soon as the pressure in the compressed air accumulator 35 falls below a third limit value Piimit,3, the pressure switch PS sends a corresponding signal to the control device AFD, which results in the pipes 9 and the loads 7, 3, and 5 being emptied.

[0038] The control device AFD also has an input from a pneumatic pressure line 37 and an output which is connected to the toilet flush 5 and the grey water tank 13. In this way, it is possible, if necessary, to operate the toilet flush 5 from the control device AFD instead of with compressed air as normally, so that the toilet flush 5 will be emptied when the second control valve 23 is closed at the same time as the toilet flush 5 is operated. Furthermore, the compressed air line 37 ensures that, if necessary, an overpressure is created in the grey water tank 13 such that any water in the grey water tank 13 can flow out via the outlet 19 into the wastewater tank (not shown) and the grey water tank 13 thereby be emptied.

[0039] The water heater 7 is emptied by the third directional valve 25 opening. In order to minimise compressed air requirements, it is advisable to close the second directional valve 23 first and then open the third directional valve 25 so that the water heater 7 drains.

[0040] The toilet flush 5 is then operated at least once by the control device AFD, and the grey water tank 13 empties in the way previously described.

[0041] In this way, it is possible to empty the entire water system with a low compressed air requirement of 120 to 150 litres, so that frost damage can no longer occur.

[0042] When the fresh water tank 1 is to be emptied, it will suffice to open the first direc- tional valve 21, since the fresh water tank 1 will empty itself due to the force of gravity of the water in it.

[0043] A flowchart of the method according to the invention is shown in Figure 2.

[0044] The method according to the invention begins at a starting block. In a first function block 51, the current voltage U of the supply system or of a battery is measured, as is, also, the pressure P in the pressure accumulator 35.

[0045] In a first query block 53, it is ascertained whether the current pressure P is below a limit value Pm,3· If this is the case, then, in a second function block 55, the valve 23 is closed and the valve 25 opened, and the toilet flush 5 also actuated. This is indicated by correspondingly labelled arrows exiting the second function block 55.

[0046] The valves 21, 23, and 25, and also the toilet flush 5, can, as already explained in connection with Figure 1, be actuated at different times so that the third directional valve 25 is opened first to allow the water heater 9 to run to empty, and only then is the toilet flush 5 operated and the grey water tank 13 aerated with compressed air. The valve 21 remains closed. The program then branches back to the beginning.

[0047] A second comparator 57 then queries whether the on-board voltage U is below a first limit value Um,i- If this should not be the case, the procedure will then branch back to the start.

[0048] If the second comparator 57 finds that the supply voltage U is below the first limit value Ulimit, 1 j the program will branch to a third function block 59. In a similar way to the second function block 55, the valves 23 and 25, as well as the toilet flush 5, are actuated there.

[0049] A check is made in a third comparator 61 whether the voltage U is below a second limit value Uiimit,2 or whether the voltage remains below the first limit value υΐΜ,ι for longer than a specified time interval ΔΤ. If this query is answered in the negative, the program will branch back to the beginning. Otherwise, the first directional valve 21 is additionally opened in a fourth function block 63.

Claims

A method for protecting the water pipes (9) and the water tanks (1, 13) in a vehicle, in particular a rail vehicle, against frost damage, wherein a voltage (U) is monitored in an electrical cable system of the vehicle and a pressure (p) is monitored in a compressed air network (37) of the vehicle, where the water lines (9) and the water tanks (5, 7, 13) are emptied when the voltage (U) falls below a first limit value (UGrenz, 1) or when the pressure (p) falls below a third limit value (pGrenz, 3) and where electrical energy is needed to carry out the process and where compressed air is needed to empty the water lines and water tanks.

Method according to claim 1, characterized in that an outlet (19) of the fresh water tank (1) is opened when the voltage (U) falls below a second limit value (UGrz, 2) or remains below the first limit value (UGrz, 1) for longer than a time interval ([Delta]).

Method according to claim 1 or 2, characterized in that it is carried out when a nominal temperature Tist is less than a limit temperature TGrz.

Process according to one of the preceding claims, characterized in that the discharge of the toilet (5) and / or of the containers with gray waste water (13) is carried out with compressed air.

Method according to claim 4, characterized in that the flushing of the toilets is effected by means of an activation at least once of the flushing (5).

Method according to one of the preceding claims, characterized in that the water lines (9) and / or the water tanks (5, 7, 13) are emptied when there is a temperature in the interior of the vehicle of less than 5 degrees.

Method according to one of the preceding claims, characterized in that the water lines (9) and / or the water tanks (1, 13) are emptied when a frost protection switch or button (31) is activated.

Control device for monitoring a freshwater system and / or domestic water system of a vehicle, in particular a rail vehicle, characterized in that it operates according to one of the preceding method requirements.

Computer program for running on a computer device, characterized in that it operates according to one of the preceding method requirements.

Water system in a vehicle, in particular a rail vehicle, comprising a fresh water tank (1), at least one consumer (3, 5, 17) and at least one water line (9), characterized in that a voltage monitor (MVR) is provided for monitoring the voltage (U) of an electrical cable system and / or pressure monitor (PS) for monitoring the pressure (p) in a compressed air storage or compressed air network and a control device (AFD) for carrying out the method according to any one of claims 1 to 7, and electrical energy is needed to carry out the process and / or compressed air is needed to empty the water pipes and water tanks.

Water system according to claim 10, characterized in that a directional switchable valve (21, 23) is provided at the inlet and outlet (9, 19) of the fresh water tank (1), respectively.

Water system according to claim 10 or 11, characterized in that a third switchable directional valve (25) is provided at an outlet of a water heater (7).

Water system according to claim 11, characterized in that a switchable directional valve (21, 23) is provided at each of the outlets (9, 19) of the fresh water tank (1).

Water system according to one of claims 10 to 13, characterized in that at least one of the switchable directional valves (21, 23, 25) is designed as a ventable directional valve.