Apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks

Abstract

 An apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, comprising two apparatus lines (11, 111), one for liquefied petroleum gas (LPG) and one for methane; each line comprises a burner (13, 113) that can be functionally connected by means of piping to a pressurized tank (12, 112) to be emptied, such as for example the storage tank of a motor vehicle; a pressure reduction block (16, 116) is arranged between the burner and the tank, and first flow control means are provided between the burner and the reduction block; second flow control means are further provided upstream of the reduction block (16, 116).

Description

[0001] The present invention relates to an apparatus for emptying fuel from pressurized tanks.

[0002] The invention relates particularly but not exclusively to an apparatus for emptying storage tanks of motor vehicles that contain liquefied petroleum gas (LPG) or methane.

[0003] Currently, when an LPG- or methane-fueled vehicle is retired, it is necessary to remove the storage tank from it, for example in order to avoid the danger of storage tank explosions during scrapping.

[0004] The law provides specific statutory provisions for retiring such tanks both for safety reasons and for environmental reasons.

[0005] According to these statutory provisions, the storage tanks must be empty when they are retired.

[0006] For this reason, the operators who remove the storage tanks from the motor vehicles require the owners to bring them empty at removal time.

[0007] The owners are therefore forced to travel "on empty" in order to discharge the storage tanks.

[0008] Even after this operation, the storage tanks still contain residues of fuel (LPG or methane) and it would be necessary to empty them completely, in practice to purge them and render them inert, before or after removing them from the motor vehicle.

[0009] Currently there are no known plants that allow to purge the storage tanks.

[0010] What operators in the field do (often in violation of specific statutory provisions) is to open the safety valves and vent the gaseous fraction of the fuel into the open air; by doing so, first of all they have no assurance that the storage tank is emptied completely (since there can always be a minimal gaseous fraction of fuel); secondly, they require an appropriate site where they can perform the operation without polluting the environment; thirdly, they must be equipped with suitable safety measures.

[0011] The aim of the present invention is to provide an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that solves the problems noted above in purging pressurized tanks such as motor vehicle storage tanks.

[0012] Within this aim, an object of the present invention is to provide an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that allows to avoid polluting the environment.

[0013] Another object of the present invention is to provide an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that allows to purge the tanks without having to move them to appropriate sites.

[0014] A further object of the present invention is to provide an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that ensures complete elimination of the residues of fuel from the inside of said tanks.

[0015] A still further object of the present invention is to provide an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that is simple and easy to manufacture.

[0016] Another object of the present invention is to provide an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that can be manufactured with known equipment and technologies.

[0017] This aim and these and other objects that will become better apparent hereinafter are achieved by an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, characterized in that it is constituted by at least one apparatus line that comprises at least one burner that can be functionally connected by means of piping to a pressurized tank to be emptied, a pressure reduction block being arranged between said burner and said tank, first flow control means being provided between said burner and said reduction block, second flow control means being provided upstream of said reduction block.

[0018] Advantageously, the apparatus further comprises at least one plant section for inertizing the residual fuel that is present inside said pressurized tank to be emptied, said section being constituted by at least one burner torch that can be functionally connected by means of ducts to said pressurized tank to be emptied, at least one pressure vessel containing inert gas being functionally connectable to said ducts, third flow control means being provided between said at least one vessel and said tank, fourth flow control means being provided between said burner torch and said vessel.

[0019] Further characteristics and advantages of the present invention will become better apparent from the following detailed description of a preferred but not exclusive embodiment thereof, illustrated by way of nonlimiting example in the accompanying drawings, wherein:

Figure 1 is a diagram of the apparatus according to the invention;

Figure 2 is an enlarged-scale view of a first part of the diagram of the apparatus according to the invention;

Figure 3 is an enlarged-scale view of a second part of the diagram of the apparatus according to the invention;

Figure 4 is an enlarged-scale view of a third part of the diagram of the apparatus according to the invention.

[0020] With reference to the figures, an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, according to the invention, is generally designated by the reference numeral 10.

[0021] The apparatus 10 is constituted by two apparatus lines: a first line, designated by the reference numeral 11, which is associable with a first pressurized tank 12 to be emptied, which contains liquefied petroleum gas (LPG); and a second line, designated by the reference numeral 111, which is associable with a second pressurized tank 112 to be emptied, which contains methane gas.

[0022] Each line is substantially characterized by similar components.

[0023] Accordingly, the first apparatus line is described hereinafter and its components are designated by two-digit numerals, while the corresponding components of the second line are designated by corresponding numerals increased by one hundred; the various differences between the two lines will be specified in each instance.

[0024] The first line comprises a burner 13, which can be functionally connected by means of piping 14 to the first pressurized tank to be emptied, such as, in this embodiment, an LPG storage tank that acts as a fuel tank for a motor vehicle (which is not shown in the figures).

[0025] The apparatus comprises means for drawing in the liquid phase from the pressurized tank to be emptied.

[0026] The liquid-phase drawing means correspond, in this embodiment, to the riser valve that is present inside the LPG storage tank, which dips directly in the liquid phase.

[0027] Between the burner 13 and the tank 12 there is a pressure reduction block 15, which is constituted by a pressure reduction unit 16 that operates continuously and is associated with heating means.

[0028] The heating means are constituted by a hydraulic circuit in which water circulates; such circuit comprises a heat exchanger 20 that is coupled to the pressure reduction unit 16.

[0029] The exchanger 20 is functionally connected in input, by means of piping, to the output of a boiler 21 for the water and in output to a plenum chamber 22 for the water and to the input of the boiler 21; in this way, the input of the boiler 21 is also functionally connected to the plenum chamber 22.

[0030] At the output of the boiler 21 there are a thermometer 21a and a minimum-temperature thermostat 21b.

[0031] Two first ball valves 23 are provided in input and in output to the exchanger 20.

[0032] The hydraulic circuit further comprises means for recirculating the water in said circuit, which are constituted by an electric pump 24 that is comprised between two second ball valves 23a.

[0033] The pressure reduction units of the first and second plant lines 11 and 111, designated respectively by the reference numerals 16 and 116, have a similar function but are structured for different fluids and for operation at different pressures.

[0034] The LPG reduction unit 16 operates from a maximum pressure of 4-5 atmospheres to approximately 0.03 atmospheres, whereas the methane reduction unit 116 operates from a maximum pressure of approximately 200 atmospheres to approximately 0.02 atmospheres; both reduction units operate continuously (without the variable flow-rate that is typical of pressure reduction units provided in output to motor vehicle storage tanks).

[0035] First flow control means are provided between the burner 13 and the pressure reduction unit 16 and are constituted by a first slow-release electric valve 30.

[0036] Upstream of the pressure reduction unit 16 there are second flow control means constituted by a third ball valve 23b.

[0037] Conveniently, the second flow control means further comprise a second electric safety valve 25, which is arranged in series to the third ball valve 23b, in particular between the third ball valve 23b and the pressure reduction unit 16.

[0038] The second electric valve 25 is associated with a low-pressure detector 52 that adjusts its operation.

[0039] Advantageously, the apparatus 10 comprises an apparatus section 40 for inertizing the residual fuel that is present inside the corresponding pressurized tank (12 or 112) to be emptied.

[0040] The inertizing section 40 is constituted by a burner torch 41 that can be functionally connected, by means of ducts 42 connected to the piping 14, to the corresponding pressurized tank 12 to be emptied.

[0041] A pressure vessel 45 containing inert gas, such as nitrogen in this embodiment, can be functionally connected to the ducts by coupling to the piping 14.

[0042] Third flow control means are provided between the vessel 45 and the tank 12 and are constituted by a third electric filler valve 46 for flushing the tank 12 with nitrogen.

[0043] In particular, the third electric valve 46 is arranged in the portion 47 that connects the pressure vessel 45 to the pipes 14.

[0044] The pressure vessel 45 containing nitrogen can be connected to the second apparatus line 111 by means of a corresponding connecting portion 147.

[0045] In the portion 147 there is a corresponding third electric filler valve 146 for flushing the tank 112 with nitrogen; a minimum nitrogen pressure-controlled switch 148 is associated with the electric valve 146.

[0046] At the output of the pressure vessel 45 (in particular between said vessel and the coupling of the portions 47 and 147) there is a nitrogen reduction element 49 to which a pressure gauge (not designated by a reference numeral for the sake of clarity) is connected.

[0047] Fourth flow control means are provided between the burner torch 41 and the vessel 45 and are constituted by a fourth electric valve 50 for venting the nitrogen used to flush the tank 12; in particular, the fourth electric valve 50 is arranged in the portion of the duct 42 between the torch 41 and the reduction unit 20.

[0048] The third electric filler valve 46 for flushing the tank 12 with nitrogen and the fourth electric valve 50 for venting the nitrogen are associated with a high-pressure detector 51, located directly downstream of the valve 23b, which adjusts its operation.

[0049] The entire apparatus 10 is enclosed in a metallic cabinet 60 that is provided with the appropriate outlets for connection to the tanks of the motor vehicles to be emptied and inertized.

[0050] In an upper region, the cabinet 60 is provided with a hood-stack 61, at the base of which the burners 13, 113 and the burner torches 41, 141 are arranged.

[0051] The burner torches 41, 141 are provided with a piezoelectric element (not shown in the figures).

[0052] The apparatus is provided with an electric control circuit that is associated with an electric control panel 70 that is inserted in a containment compartment (not shown in the figures) of the electrical panel, which is formed in the cabinet 60 and is provided with its own door.

[0053] The electrical panel 70 contains a switch for switching operation from LPG gas to neutral and from neutral to methane gas, pushbuttons with a warning light to indicate the start of the cycle with LPG gas and with methane gas, a switch for locking the opening of the door of said containment compartment of the electrical panel, an optical and acoustic indicator of nitrogen gas depletion, and indicators of sequence in progress.

[0054] Further, the apparatus comprises a one-way valve 65, 165, which is arranged downstream of the third electric valve 46, 146 with respect to the pressure vessel 45.

[0055] Moreover, the apparatus comprises a flashback arrester 67, 167, which is arranged upstream of the burner torch 41, 141.

[0056] Control and management of the apparatus is entrusted to an electronic control unit (not present in the figures), which is associated with a PLC (Programmable Logic Controller).

[0057] The operation of the invention is as follows.

[0058] With reference to the first plant line 11, the LPG tank 12 of a motor vehicle is connected so that the piping 14 dips in the liquid phase from the tank 12, and the valve 23b and the electric valves 30 and 25 are opened, while the electric valves 46 and 50 of the inertizing section are closed.

[0059] The LPG changes from a liquid to a gas through the pressure reduction unit 16, which is heated in order to prevent it from freezing during vaporization, by means of the exchanger 20, by the hot water heated by the boiler 21.

[0060] Through the piping 14, the gas reaches the burner 13, which bums it.

[0061] When all of the liquid phase has been extracted from the inside of the tank 12, the resulting pressure is minimal and is such that the residual gaseous phase does not allow combustion by the burner 13.

[0062] At this point, a first cycle for flushing on the part of the inertizing section 40 is started.

[0063] The electric valve 30 is closed and the electric valve 46 is opened; the nitrogen, which is at a higher pressure, flows inside the tank and mixes with the gaseous residues of the LPG.

[0064] At this point, the electric valve 46 is closed and the electric valve 50 is opened.

[0065] The mixture of nitrogen and LPG is thus burned by the torch 41 (the mixture is ignited by the piezoelectric element, which operates continuously).

[0066] After a certain time, the mixture is so poor in LPG that it no longer burns.

[0067] The electric valve 50 is closed and the electric valve 46 is reopened, starting a new nitrogen flushing cycle.

[0068] The duration of said cycles is controlled by the high-pressure detector, which regulates the opening and closing of the electric valves 46 and 50.

[0069] The first washing cycle is sufficient to purge the tank, but for safety, in order to eliminate any minimal traces of residual propane, at least three cycles are performed in all.

[0070] In the cycles after the first one, the torch no longer bums, since there is not enough propane to burn, and discharges almost exclusively nitrogen; in any case, for safety, the piezoelectric element is operated continuously.

[0071] In practice it has been found that the invention thus described solves the problems noted above in the emptying of pressurized tanks filled with fuel; in particular, the present invention provides an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that does not require removal of the storage tanks from the motor vehicles.

[0072] Moreover, the present invention provides an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that allows to vent the storage tanks completely.

[0073] It should be noted that the fact of dipping in the liquid phase from the storage tank ensures depletion of the entire liquid fraction.

[0074] Further, the present invention provides an apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, that limits pollution to the ordinary burnt residues of the combustion of the burner torch and of the burner.

[0075] The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

[0076] In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art.

[0077] The disclosures in Italian Patent Application No. PD2003A000035 from which this application claims priority are incorporated herein by reference.

[0078] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. An apparatus for emptying fuel from pressurized tanks, particularly for motor vehicle storage tanks, characterized in that it is constituted by at least one apparatus line that comprises at least one burner that can be functionally connected by means of piping to a pressurized tank to be emptied, a pressure reduction block being arranged between said burner and said tank, first flow control means being provided between said burner and said reduction block, second flow control means being provided upstream of said reduction block.

2. The apparatus according to claim 1, characterized in that it comprises at least one plant section for inertizing the residual fuel that is present inside said pressurized tank to be emptied, said section being constituted by at least one burner torch that can be functionally connected by means of ducts to said pressurized tank to be emptied, at least one pressure vessel containing inert gas being functionally connectable to said ducts, third flow control means being provided between said at least one vessel and said tank, fourth flow control means being provided between said burner torch and said vessel.

3. The apparatus according to claim 2, characterized in that said third and fourth flow control means are associated with at least one high gas pressure detector.

4. The apparatus according to claim 2, characterized in that said inert gas is nitrogen.

5. The apparatus according to one or more of the preceding claims, characterized in that it comprises means for dipping in the liquid phase from said pressurized tank to be emptied.

6. The apparatus according to one or more of the preceding claims, characterized in that said pressure reduction block is constituted by at least one pressure reduction unit that operates continuously and is associated with heating means.

7. The apparatus according to claim 6, characterized in that said heating means are constituted by a hydraulic circuit that comprises at least one heat exchanger that is coupled to said at least one pressure reduction unit, said exchanger being functionally connected in input to the output of a water boiler and in output to a plenum chamber for the water that circulates in said circuit and to the input of said boiler, said boiler and said plenum chamber being functionally connected to each other, said circuit further comprising means for recirculating the water in said circuit.

8. The apparatus according to claim 7, characterized in that a thermometer and a minimum-temperature thermostat are provided in output to said water boiler.

9. The apparatus according to one or more of the preceding claims, characterized in that said first flow control means comprise a first slow-release electric valve.

10. The apparatus according to one or more of the preceding claims, characterized in that said second flow control means comprise a ball valve.

11. The apparatus according to one or more of the preceding claims, characterized in that said second flow control means comprise a second electric safety valve.

12. The apparatus according to claims 6, 10 and 11, characterized in that said second electric safety valve is arranged between said third ball valve and said pressure reduction unit, said second electric safety valve being associated with a low-pressure detector that adjusts its operation.

13. The apparatus according to one or more of the preceding claims, characterized in that said third flow control means comprise a third electric filler valve for flushing said tank with nitrogen.

14. The apparatus according to one or more of the preceding claims, characterized in that said fourth flow control means comprise a fourth electric valve for discharging the nitrogen used to flush said tank.

15. The apparatus according to one or more of the preceding claims, characterized in that liquefied petroleum gas (LPG) or methane is present inside said pressurized tank to be emptied.

16. The apparatus according to one or more of the preceding claims, characterized in that it comprises two of said at least one plant lines, a first line that can be associated with a first pressurized tank to be emptied, which contains liquefied petroleum gas (LPG), and a second line that is associable with a second pressurized tank to be emptied, which contains methane.

17. The apparatus according to claim 16, characterized in that it comprises a single apparatus section for inertizing the residual fuel that is present inside said first and second pressurized tanks to be emptied.

18. The apparatus according to one or more of the preceding claims, characterized in that it comprises at least one one-way valve that is arranged downstream of said third electric valve with respect to said pressurized tank.

19. The apparatus according to one or more of the preceding claims, characterized in that it comprises at least one pressure detector that is arranged respectively upstream of said burner device and downstream of said first tank.

20. The apparatus according to one or more of the preceding claims, characterized in that it comprises at least one flashback arrester, which is arranged upstream of said burner torch.

21. The apparatus according to one or more of the preceding claims, characterized in that it comprises an electronic control unit for management and control that is associated with a PLC.

Drawing