Electronic flow sensor

Abstract

A safety shut-off device is provided for a liquid gas system for vehicles and/or vehicle trailers, in order to avoid an inadvertent release of gas. The device includes an electromagnetic gas valve for supplying/shutting off the gas, an electronic unit for activating the electromagnetic gas valve, and a flow sensor for determining a current gas flow being discharged from a storage tank. Furthermore, the device includes an evaluation unit for comparing the current gas flow to a previous gas flow or to a gas flow which is indicated by the gas consumers and is to be expected. If, during use, the evaluation unit determines a current gas flow which differs by more than a maximum permissible rate of change from the previous gas flow or from an expected gas flow, the electromagnetic gas valve is activated via the electric unit in order to shut off the supply of gas.

Claims

1. A safety shut-off device for a liquid gas system having at least one gas consumer for a vehicle and/or vehicle trailer for avoiding an unwanted release of gas, the device comprising: a) an electromagnetic gas valve for shutting off a gas supply to the liquid gas system; b) a flow sensor for periodically detecting a current gas flow F.sub.a being discharged from a gas source; c) an evaluation unit that, for each time a current gas flow F.sub.a is detected by the flow sensor, compares the current gas flow F.sub.a to an immediately preceding detected gas flow F.sub.v; and d) an electronic unit which controls the electromagnetic gas valve for shutting off the gas supply when the evaluation unit detects a current gas flow F.sub.a which differs from the immediately preceding detected gas flow F.sub.v by more than a maximum admissible gas flow change rate .sub.max, such that the gas supply is shut off when the following condition is fulfilled: F.sub.a F.sub.v>.sub.max.

2. The safety shut-off device according to claim 1, wherein the maximum admissible gas flow change rate A.sub.max is calculated according to a consumption value of a largest gas consumer of the liquid gas system.

3. The safety shut-off device according to claim 2, wherein the maximum admissible gas flow change rate .sub.max is higher than the consumption value for the largest gas consumer F.sub.G by a tolerance value of less than 30%.

4. The safety shut-off device according to claim 1, wherein the maximum admissible gas flow change rate .sub.max is adjustable based on current gas flow consumption information of the gas consumers.

5. The safety shut-off device according to claim 4, wherein the electronic unit obtains from each of the gas consumers information regarding whether the respective gas consumer is switched on or off, as well as an expected gas consumption amount for the respective gas consumer.

6. The safety shut-off device according to claim 5, wherein the information is obtained by the electronic unit via a bus system.

7. The safety shut-off device according to claim 1, wherein the evaluation unit is in active communication with an information output unit for outputting at least one of the following items of information: the current gas flow; gas flow integrated over a period of time; gas flow integrated over time since a replacement of a gas bottle; a currently available residual amount in a gas bottle or a gas reservoir; and an alarm indication upon falling below a predefined residual amount.

8. The safety shut-off device according to claim 1, wherein the electromagnetic gas valve shuts off the gas supply in the liquid gas system in absence of an electrical energy supply.

9. The safety shut-off device according to claim 1, wherein the electromagnetic gas valve is gas-fluidically connected downstream of a pressure regulator.

10. The safety shut-off device according to claim 9, wherein the electromagnetic gas valve is directly mounted to the pressure regulator.

11. The safety shut-off device according to claim 9, wherein the pressure regulator is directly mounted or mountable to a gas reservoir constituting the gas source.

12. The safety shut-off device according to claim 1, wherein the electromagnetic gas valve is gas-fluidically connected upstream of a pressure regulator.

13. The safety shut-off device according to claim 12, wherein the electromagnetic gas valve is directly mounted or mountable to a gas reservoir constituting the gas source.

14. The safety shut-off device according to claim 12, wherein the electromagnetic gas valve is directly mounted to the pressure regulator.

15. The safety shut-off device according to claim 1, wherein the electromagnetic gas valve is connected or connectable to a battery installed in the vehicle and/or vehicle trailer.

16. The safety shut-off device according to claim 1, further comprising a switch optionally arranged in an interior of the vehicle or vehicle trailer for manually switching off the gas supply.

17. The safety shut-off device according to claim 1, further comprising at least one hazard sensor to detect a hazardous situation in the vehicle and/or vehicle trailer, wherein the at least one hazard sensor is in communication with the electronic unit for transmitting a danger signal.

18. The safety shut-off device according to claim 17, wherein the electronic unit and/or at least hazard sensor is configured such that the electromagnetic gas valve automatically shuts off the gas supply in case of hazard.

19. A liquid gas system for vehicles and/or vehicle trailers, the system comprising: a) at least one gas reservoir connected or connectable to at least one gas consumer via at least one gas line; and b) a safety shut-off device according to claim 1 for avoiding an unwanted release of gas.

20. A method for operating a safety shut-off of a liquid gas system for vehicles and/or vehicle trailers for avoiding an unwanted release of gas, the system including at least one gas reservoir connected or connectable to at least one gas consumer via at least one gas line, and a safety shut-off device, the safety shut-off device including an electromagnetic gas valve for shutting off a gas supply to the liquid gas system, a flow sensor for periodically detecting a current gas flow F.sub.a being discharged from the at least one gas reservoir, an evaluation unit that, for each time a current gas flow F.sub.a is detected by the flow sensor, compares the current gas flow F.sub.a to an immediately preceding detecting gas flow F.sub.v, and an electronic unit which controls the electromagnetic gas valve for shutting off the gas supply, the method comprising the following steps: a) detecting, using the flow sensor, a current gas flow F.sub.a exiting the gas source; b) comparing, using the evaluation unit, the current gas flow F.sub.a to a previous gas flow; and c) interrupting, using the electronic unit, the gas supply via the electromagnetically controlled gas valve when the comparing step finds the current gas flow F.sub.a differs from the immediately preceding detected gas flow F.sub.v by more than a maximum admissible gas flow change rate .sub.max, such that the gas supply is interrupted when the following condition is fulfilled: F.sub.a F.sub.v>.sub.max.

21. The method according to claim 20, wherein step a) occurs following an accident befalling the vehicle and/or vehicle trailer.

22. The method according to claim 20, wherein the step of interrupting the gas supply comprises interrupting a power supply to the electromagnetic gas valve to shut off the liquid gas system.

23. The method according to claim 20, wherein the maximum admissible gas flow change rate .sub.max is fixedly preselected for or adapted to at least one of the following: a given configuration of the liquid gas system, a current consumption situation, and a consumption situation to be expected, while the liquid gas system is in operation.

24. The safety shut-off device according to claim 17, wherein the at least one hazard sensor is a gas sensor and/or smoke detector to detect gas leakage and/or fire.

25. A safety shut-off device for a liquid gas system having at least one gas consumer for a vehicle and/or vehicle trailer for avoiding an unwanted release of gas, the device comprising: a) an electromagnetic gas valve for shutting off a gas supply to the liquid gas system; b) a flow sensor for periodically detecting a current gas flow F.sub.a being discharged from a gas source; c) an evaluation unit that, for each time a current gas flow F.sub.a is detected by the flow sensor, compares the current gas flow F.sub.a to an admissible maximum gas flow F.sub.max; and d) an electronic unit which controls the electromagnetic gas valve for shutting off the gas supply when the evaluation unit detects a current gas flow F.sub.a which is higher than the admissible maximum gas flow F.sub.max, wherein the admissible maximum gas flow F.sub.max is calculated according to a sum of all gas flow consumption values F.sub.s of the gas consumers of the liquid gas system, and wherein the admissible maximum gas flow F.sub.max is updated by current and/or expected gas consumption values signaled by the gas consumers.

26. The safety shut-off device according to claim 25, wherein the admissible maximum gas flow F.sub.max is higher than the sum of all the consumption values F.sub.s of the gas consumers of the liquid gas system by a tolerance value of less than 25%.

27. The safety shut-off device according to claim 25, wherein the admissible maximum gas flow F.sub.max is adjustable based on current gas flow consumption information of the gas consumers.

28. The safety shut-off device according to claim 27, wherein the electronic unit obtains from each of the gas consumers information regarding whether the respective gas consumer is switched on or off, as well as an expected gas consumption amount for the respective gas consumer.

29. The safety shut-off device according to claim 28, wherein the information is obtained by the electronic unit via a bus system.

30. The safety shut-off device according to claim 25, wherein the evaluation unit is in active communication with an information output unit for outputting at least one of the following items of information: the current gas flow; gas flow integrated over a period of time; gas flow integrated over time since a replacement of a gas bottle; a currently available residual amount in a gas bottle or a gas reservoir; and an alarm indication upon falling below a predefined residual amount.

31. The safety shut-off device according to claim 25, wherein the electromagnetic gas valve shuts off the gas supply in the liquid gas system in absence of an electrical energy supply.

32. The safety shut-off device according to claim 25, wherein the electromagnetic gas valve is gas-fluidically connected downstream of a pressure regulator.

33. The safety shut-off device according to claim 32, wherein the electromagnetic gas valve is directly mounted to the pressure regulator.

34. The safety shut-off device according to claim 32, wherein the pressure regulator is directly mounted or mountable to a gas reservoir constituting the gas source.

35. The safety shut-off device according to claim 25, wherein the electromagnetic gas valve is gas-fluidically connected upstream of a pressure regulator.

36. The safety shut-off device according to claim 35, wherein the electromagnetic gas valve is directly mounted or mountable to a gas reservoir constituting the gas source.

37. The safety shut-off device according to claim 35, wherein the electromagnetic gas valve is directly mounted to the pressure regulator.

38. The safety shut-off device according to claim 25, wherein the electromagnetic gas valve is connected or connectable to a battery installed in the vehicle and/or vehicle trailer.

39. The safety shut-off device according to claim 25, further comprising a switch optionally arranged in an interior of the vehicle or vehicle trailer for manually switching off the gas supply.

40. The safety shut-off device according to claim 25, further comprising at least one hazard sensor to detect a hazardous situation in the vehicle and/or vehicle trailer, wherein the at least one hazard sensor is in communication with the electronic unit for transmitting a danger signal.

41. The safety shut-off device according to claim 40, wherein the electronic unit and/or at least hazard sensor is configured such that the electromagnetic gas valve automatically shuts off the gas supply in case of hazard.

42. A liquid gas system for vehicles and/or vehicle trailers, the system comprising: a) at least one gas reservoir connected or connectable to at least one gas consumer via at least one gas line; and b) a safety shut-off device according to claim 25 for avoiding an unwanted release of gas.

43. A method for operating a safety shut-off of a liquid gas system for vehicles and/or vehicle trailers for avoiding an unwanted release of gas, the system including at least one gas reservoir connected or connectable to at least one gas consumer via at least one gas line, and a safety shut-off device, the safety shut-off device including an electromagnetic gas valve for shutting off a gas supply to the liquid gas system, a flow sensor for periodically detecting a current gas flow F.sub.a being discharged from the at least one gas reservoir, an evaluation unit that, for each time a current gas flow F.sub.a is detected by the flow sensor, compares the current gas flow F.sub.a to an admissible maximum gas flow F.sub.max that is calculated according to a sum of all gas flow consumption values F.sub.s of the gas consumers of the liquid gas system, and an electronic unit which controls an electromagnetically controlled gas valve for shutting off the gas supply, the method comprising the following steps: a) detecting, using the flow sensor, a current gas flow F.sub.a exiting the gas source; b) comparing, using the evaluation unit, the current gas flow F.sub.a to an admissible maximum gas flow F.sub.max; and c) interrupting, using the electronics unit, the gas supply via an electromagnetically controlled gas valve when the comparing step finds the current gas flow is greater than the admissible maximum gas flow F.sub.max, and wherein the admissible maximum gas flow F.sub.max is updated by current and/or expected gas consumption values signaled by the gas consumers.

44. The method according to claim 43, wherein wherein step a) occurs following an accident befalling the vehicle and/or vehicle trailer.

45. The method according to claim 43, wherein the step of interrupting the gas supply comprises interrupting a power supply to the electromagnetic gas valve to shut off the liquid gas system.

46. The method according to claim 43, wherein the admissible maximum gas flow F.sub.max is fixedly preselected for or adapted to at least one of the following: a given configuration of the liquid gas system, a current consumption situation, and a consumption situation to be expected, while the liquid gas system is in operation.

47. The safety shut-off device according to claim 40, wherein the at least one hazard sensor is a gas sensor and/or smoke detector to detect gas leakage and/or fire.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. The invention will be explained below also with respect to further features and advantages using the description of exemplary embodiments and with reference to the attached drawings. In the drawings:

(2) FIG. 1 is a schematic diagram of one embodiment of the inventive safety shut-off device and the inventive liquid gas system;

(3) FIG. 1a is a schematic diagram of another embodiment of the inventive safety shut-off device and the inventive liquid gas system; and

(4) FIG. 2 is a flow chart of the current gas flow over a given period of time for a liquid gas system such as that shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

(5) A basic set-up of a liquid gas system for a vehicle and/or vehicle trailer 50, including one embodiment of an inventive safety shut-off device 27, is illustrated in FIG. 1. The liquid gas system 11 first comprises two gas reservoirs 19, 20 connected via feed lines 30 to a changeover switch 29 concurrently integrating a pressure regulator 24. In addition, a hose rupture protection 28 may in each case be arranged within the feed lines 30. The changeover switch 29 works as follows: when two full gas reservoirs 19, 20 are connected, the changeover switch 29 is adjusted so that gas is withdrawn from the preselected gas reservoir. When this gas reservoir runs empty, the changeover switch 29 automatically switches over to the second full gas reservoir.

(6) The changeover switch 29 in the present embodiment automatically switches from the empty to the full gas reservoir (and may also be controllable by an electronic unit 13 still to be mentioned), so that gas can be selectively withdrawn from either gas reservoir 19 or gas reservoir 20. In most cases of application, it would be reasonable to first empty a first gas reservoir and then switch over to the second gas reservoir.

(7) Which gas reservoir is currently selected may also be output via an information output unit 21, e.g., a display screen.

(8) The gas is conducted via gas lines 26 to a plurality of gas consumers 16 to 18 by the changeover switch 29 or by the pressure regulator 24. Immediately downstream of the changeover switch 29, an electromagnetic gas valve 12 with a downstream flow sensor 14 is provided. The electromagnetic gas valve is configured so as to interrupt a gas flow to the gas consumers 16 to 18, this preferably taking place by interrupting a power supply, such as a battery 40 installed in the vehicle and/or vehicle trailer 50, for the electromagnetic gas valve 12. In this respect, the electromagnetic gas valve 12 remains open as long as a predetermined electric potential is provided. If this electric potential decreases or is 0, the electromagnetic gas valve closes and interrupts the gas supply to the plurality of gas consumers 16 to 18.

(9) The flow sensor 14 is capable of detecting a current gas flow F.sub.a to the gas consumers 16 to 18. The current gas flow F.sub.a is thereby transmitted to an evaluation unit 15. In this embodiment, the evaluation unit 15 compares the current gas flow F.sub.a both to an admissible maximum gas flow F.sub.max, calculated from the sum of all the consumption values F.sub.s for the gas consumers 16 to 18 of the liquid gas system, as well as to a previous gas flow F. For this purpose, the respectively sampled current gas flow F.sub.a is stored in the evaluation unit, so that it is available to the next polling cycle as the previous gas flow F.sub.v. In the present embodiment, the current gas flow F.sub.a is thus simultaneously subjected to two plausibility tests, namely whether it is higher than the total admissible maximum gas flow F.sub.max on the one hand and, on the other hand, whether a maximum admissible change rate .sub.max is exceeded as compared to a previous gas flow F. If one of these two cases is present, i.e., the evaluation unit assesses a current gas flow F.sub.a seeming implausible under the criteria of the liquid gas system 11, a closing or error signal is transmitted to an electronic unit 13, which brings the electromagnetic gas valve 12 into a closed position. Specifically, the electronic unit 13 would in this case interrupt the power supply for the electro-magnetic gas valve 12, so that the latter closes automatically. The electronic unit 12 and the evaluation unit 15 are preferably also in active communication with the information output unit 21, such that the data acquired by the evaluation unit 15 can be output as processed data, as need be, and the current states of the liquid gas system are displayed, such as the current gas flow F.sub.a, a previous gas low F.sub.v, the defined system parameters .sub.max and F.sub.max, the consumption value for the largest gas consumer F.sub.G, the sum of all the consumption values for the gas consumers of the liquid gas system F.sub.s, a gas consumption which has occurred since the last change of bottles, a residual amount of gas in the respective current gas reservoir, as well as further information and/or any desired subcombinations thereof.

(10) The safety shut-off device 27 illustrated here merely as an example further comprises two accident sensors as a facultative arrangement, or for further increasing safety, namely an acceleration sensor 22 and an inclination sensor 23, so that an accident may be concluded from a response of at least one of the two sensors, and this information also effects a closing of the electromagnetic gas valve 12 in the electronic unit 13 by interrupting the power supply.

(11) Finally, a manual switch 25 may further be provided, e.g., in the interior of the vehicle or vehicle trailer 50, which, for example, likewise causes a closing of the electromagnetic gas valve by the electronic unit 13 interrupting the power supply to the electro-magnetic gas valve 12. The changeover switch 29 cited above can also be connected to the electronic unit 13 so that the electronic unit 13 receives a signal from the changeover switch 29 indicating that a changeover has occurred and a corresponding display or evaluation may take place.

(12) FIG. 1a discloses an embodiment of the safety shut-off device 27 that is very similar to the one shown in FIG. 1, with the difference being that the electromagnetic gas valve 12 is shown fluidically connected upstream of the pressure regulator 24.

(13) For mere illustrative purposes, a possible gas consumption over time is depicted in FIG. 2, wherein an increase in the current gas flow F.sub.a as compared to a previous gas flow F.sub.v has taken place as the last event, the increase being above a maximum admissible change rate .sub.max, so that a shut-off of the electromagnetic gas valve 12 is thereby effected via the evaluation unit 15 and the electronic unit 13.

(14) The safety shut-off device 27 thus shuts off the gas supply when
F.sub.aF.sub.v>.sub.max (first alternative of an implausible gas consumption)
or
F.sub.a>F.sub.max (second alternative of an implausible gas consumption).

(15) As already mentioned several times above, only one of the two plausibility tests need be performed according to the invention. Preferably, both of the plausibility tests are performed, and a shut-off is effected upon even just one of the plausibility tests returning an implausible gas consumption.

(16) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.