Diffuser, tank and cleaning method

Abstract

The invention relates to a diffuser (10) for a tank (1) of pressurized gas, such as pressurized hydrogen, wherein the diffuser (10) is inside the tank (1) and is designed to inject pressurized gas. The invention also relates to a tank (1) comprising such a diffuser (10). The invention also relates to a method for purge-cleaning such a tank (1).

Description

TECHNICAL FIELD

[0001] The invention relates to a diffuser for a tank of pressurized gas, such as pressurized hydrogen, wherein the diffuser is inside the tank and shaped for injecting pressurized gas. BACKGROUND

[0002] The purging of a gas tank is an operation that allows new gas to replace old gas until the concentration of new gas in the tank exceeds a given threshold.

[0003] It is known to use a dilution method to purge a tank initially containing old gas. In such a method, a first step is to fill the tank with new pressurized gas. The tank then contains a mixture of new and old gas. In a second step, the gas mixture contained in the tank is drawn out. The purging is continued by successively repeating a cycle of these two steps. At each repetition, the mixture becomes more and more new gas and less and less old gas. Once the concentration of new gas is considered acceptable, i.e. above a given threshold, the method is stopped.

[0004] One advantage of this method is that it can be carried out with the aid of a single fluid device, which can be used both for filling and for drawing out, and which is therefore generally pre-existing on any tank, which fluid device is necessary for its nominal use.

[0005] The main disadvantage of this method is that it requires a large number of dilution cycles, resulting in a purging time that is too long.

[0006] An alternative to the dilution method is therefore sought. SUMMARY

[0007] The invention provides a method of purging a tank by purging. The principle of the purging purging method is to inject new gas by one fluid device and to simultaneously recover the gas mixture by another fluid device. This method requires a tank adapted for purging by purging. A diffuser is used to facilitate the purging by purging.

[0008] The invention relates to a diffuser for a tank of pressurized gas, such as pressurized hydrogen, wherein the diffuser is inside the tank and designed to inject pressurized gas.

[0009] Particular features or embodiments that can be used individually or in combination are:

[0010] - the diffuser extends through at least one passage that forms an angle of less than 90° with the diffuser,

[0011] - said at least one passage comprises at least two passages angularly equidistantly spaced around the diffuser,

[0012] - said at least two passages are not coplanar with the diffuser so as to swirl the injected gas,

[0013] - said at least one channel is a 360° circular around the diffuser,

[0014] - said at least one channel rotates around the diffuser.

[0015] The invention also relates to a tank for pressurized gas, such as pressurized hydrogen, comprising such a diffuser.

[0016] Particular features or embodiments that can be used individually or in combination are:

[0017] - the tank comprises a first fluidic device comprising at least one first valve adapted to allow the tank to be evacuated and a second fluidic device comprising at least one second valve adapted to allow the tank to be filled, wherein the second fluidic device comprises the diffuser,

[0018] - the first fluidic device is arranged at a first end of the tank and the second device is arranged at a second end of the tank opposite the first end.

[0019] The invention also relates to a method for purging a cleaning tank using a cleaning tool, the method comprising the steps of:

[0020] - connecting simultaneously or in any order an outlet of the cleaning tool to the second valve and an inlet of the cleaning tool to the first valve,

[0021] - opening simultaneously or in any order the first valve and possibly the second valve,

[0022] - delivering new pressurized gas via the outlet of the cleaning tool and recovering exhaust gas via the inlet of the cleaning tool for a predetermined cleaning time,

[0023] - closing the first valve,

[0024] - stopping the gas supply when the desired gas pressure is reached in the tank,

[0025] - if necessary, closing the second valve. BRIEF DESCRIPTION OF DRAWINGS

[0026] The invention will be better understood by reading the following description, given solely by way of example, and in reference to the appended drawings, in which:

[0027] [ Figure 1 ] shows an axial cross-sectional view of a tank according to a first embodiment,

[0028] [ Figure 2 ] shows an axial cross-sectional view of a tank according to a second embodiment,

[0029] Figure 3 Fig. 6 shows an axial cross-sectional view of the end of the tank,

[0030] Figure 4 Fig. 7 shows a front view of the end of the tank, Figure 3

[0031] Figure 5 Fig. 8 shows the principle of a purge,

[0032] Figure 6 Fig. 9 shows a longitudinal cross-sectional view of a first embodiment of the diffuser,

[0033] Figure 7 Fig. 10 shows a perspective view of the diffuser of Figure 6

[0034] Figure 8 Fig. 11 shows a longitudinal cross-sectional view of the diffuser of Figure 6

[0035] Figure 9 Fig. 12 shows a longitudinal view of the diffuser of

[0036] Figure 10 Fig. 13 shows a lateral cross-sectional view of a detail of the diffuser of Figure 9

[0037] Figure 11 Fig. 14 shows a perspective view of a further embodiment of the diffuser,

[0038] Figure 12 Fig. 15 shows a longitudinal view of the diffuser of Figure 11

[0039] List of reference signs

[0040] 1 : tank, 2: first fluid device, 3: second fluid device, 4: first valve, 5: second valve, 6: check valve, 7: simple valve, 8: first end, 9: second end, 10: diffuser, 11 : channel, 12: front, 13: cavity, 14: hollow space, 15: vane, 16: cover, 17: conduit, A: axis, a, b: angle. DETAILED DESCRIPTION

[0041] Reference is made to Figure 1 or Figure 2 ​​​​​​​​​​​​​​​This invention relates to a tank 1 for pressurizing gases such as pressurized hydrogen. The tank 1 includes a first fluid device 2. For the purposes of this cleaning method, the first fluid device 2 includes at least one first valve 4 adapted for suction from the tank 1. The first fluid device 2 may have other functions. Advantageously, the first fluid device 2 is a fluid device 2 known in the prior art, used throughout the entire service life of the tank 1. It is also referred to as an OTV (over-tank valve). Such a fluid device 2 can be used to suction from and fill the tank 1. It also provides monitoring and safety functions, such as pressure and / or temperature monitoring, or gas release in the event of critical overpressure.

[0042] Depending on the features applicable to a purging cleaning method, the tank 1 also includes a second fluid device 3. This second fluid device 3 may be referred to as an "end plug" (EP). The second fluid device 3 includes at least one second valve 5 suitable for filling.

[0043] like Figure 3 As shown, according to another feature, the second fluid device 3 also includes a diffuser 10. The diffuser 10 is located inside the tank 1 and points substantially towards the interior of the tank 1 along axis A, thereby connecting the first fluid device 2 to the second fluid device 3. The diffuser connects the second fluid device 3 to the interior of the tank 1. The diffuser 10 is designed to inject pressurized gas into the tank 1.

[0044] like Figure 3 and Figure 4 As shown, another advantageous feature is that the diffuser 10 extends inward through at least one channel 11. The at least one channel 11 advantageously forms an angle α less than 90° with the diffuser 10, and therefore an angle α less than 90° with the axis A. Furthermore, the channel 11 allows new gas introduced through the second valve 5 to be “blown” toward a backflow, stop, or dead zone at the bottom of the tank 1, which would otherwise remain outside the purging range.

[0045] The length of the pressurized gas jet can be easily adjusted by adjusting the cumulative flow cross-section of the nozzle 11 relative to the flow cross-section of the diffuser 10.

[0046] According to another advantageous feature, the at least one channel 11 comprises at least two channels 11, and preferably three or four channels 11. These channels 11 are advantageously spaced at equal angles around the diffuser 10. Figure 4 An example with three channels 11 arranged at β = 120° is shown. Increasing the number of channels 11 can advantageously improve the dead zone purging effect. The uniform distribution of channels 11 helps to homogenize the purging process.

[0047] This acute angle feature is due to Figures 6 to 8The diffuser 10 shown is illustrated. The diffuser 10 is made of a pressed metal sheet. It can be a sheet of metal, such as a light alloy. Alternatively, this diffuser 10 can be made of plastic, typically by injection molding. The diffuser 10 includes a generally cylindrical body adapted to be press-fitted into the end of a conduit of the second device 3. At the other end of the diffuser 10, the diffuser includes a cap 16 with cavities 14 to help guide the diffused gas jet. The sides of the diffuser 10 are pierced by cavities 13. These cavities 13 form channels 11. The shape of the cavities 13 allows the gas jet to be guided at an acute angle α. This embodiment is a simple and inexpensive way to manufacture a diffuser.

[0048] According to another feature, the at least two channels 11 are not coplanar with the diffuser 10. This angular offset (which is advantageously the same for all channels 11) generates a tangential component that causes the injected gas to vortex. This vortex improves the cleaning of the tank 1.

[0049] This vortex characteristic is due to Figure 9 and Figure 10 An embodiment of the diffuser 10 shown is illustrated. In this embodiment, the diffuser 10 includes segmented assembled blades 15 preceding the end cap 16.

[0050] These blades 15 form channels 11 between the blades. The radially curved shape of these channels 11 generates a vortex effect that entrains gas jets.

[0051] Of course, it's possible to combine the two features mentioned above: acute angles and vortices. This is achieved through... Figure 11 and Figure 12 An embodiment of the diffuser 10 shown is illustrated. Conduits 16 are formed inside the diffuser 10. These conduits 16 form channels 11. They are at acute angles to the axis. They also have a radially curved shape such that they are not coplanar with the diffuser 10. In this way, they induce a vortex effect applied to the gas jet while guiding the gas jet toward the dead zone of the tank 1.

[0052] According to another feature (not shown), the characteristics of increasing the number of channels 11 to infinity are summarized, resulting in a single 360° circular channel 11 rotating around the diffuser 10. This produces a conical jet, increasing the area swept by the pressurized gas.

[0053] According to another feature (not shown), the at least one channel 11 rotates around the diffuser 10. This rotation can be achieved, for both the discrete channel 11 and the single circular channel, by a rotational degree of freedom obtained by any known means and supplemented by the prior non-coplanarity characteristic. In this way, the channel 11 rotates freely around the diffuser 10, and the pressurized gas generates rotation by passing through the channel 11.

[0054] According to another feature, the second valve 5 is a check valve 6. This check valve (6) is oriented to open in the direction from the outside to the inside of the tank 1 and to block in the other direction. This preferred design allows for automation of the cleaning method because the second valve 5 opens by applying cleaning pressure in the direction from the outside to the inside of the tank 1 without manual intervention.

[0055] According to another feature, the second valve 5 is a simple valve 7, preferably a manual valve. Advantageously, this simple manual valve 7 is cheaper than the previously designed check valve 6. However, this embodiment is a degraded embodiment relative to the previous embodiment because it requires manual operation of the simple valve 7 to open when cleaning pressure is applied.

[0056] According to another feature, the second valve 5 includes a check valve 6 and a simple valve 7 connected in series, preferably a manual valve. This ensures redundant sealing to the outside. Although more expensive than the aforementioned method, this implementation improves the safety of tank 1.

[0057] According to another feature, the first fluid device 2 is arranged at the first end 8 of the tank 1, and the second fluid device 3 is arranged at the second end 9 of the tank 1 opposite to the first end 8.

[0058] Even more advantageously, for a tank 1 having a longitudinal extension along axis A, the two fluid devices 2, 3 are preferably arranged at the respective ends of the extension. In this way, the front portion 12 between the old "fluid A" gas and the new "fluid B" gas has the minimum possible surface area, i.e., the cross-section of tank 1 perpendicular to the extension axis. Figure 5 As shown, this optimizes the removal of old "fluid A" gas by new "fluid B" gas during cleaning, thus promoting and / or accelerating cleaning.

[0059] The present invention also relates to a method for purging and cleaning such a tank 1. The method uses a cleaning tool. This cleaning tool typically includes a first conduit comprising an outlet connector adapted for sealingly connecting to a second valve 5 and adapted for supply by a new gas supply device, which includes, for example, a new gas tank and a pump. The cleaning tool also includes a second conduit having an inlet connector capable of sealingly connecting to the first valve 4, so that the gas mixture leaving the tank 1 can be discharged and, if necessary, recovered. In its simplest form, the second conduit includes an exhaust passage. Alternatively, it includes a storage device, such as a tank, adapted for storing the discharged mixture.

[0060] The cleaning method includes the following steps: A cleaning tool is placed on the tank 1 to be cleaned. For this purpose, in a first step, the output of the cleaning tool is connected to a second valve 5, and in a second, earlier, simultaneous, or later step, the input of the cleaning tool is connected to a first valve 4.

[0061] In the third step, the first valve 4 is opened. If the first valve 4 is an OTV discharge valve, it can be a solenoid valve that can be electrically controlled by a control device, which may be grouped with or integrated with a cleaning tool controller. Alternatively, it can also be a manual valve, operated manually or by a tool. This first opening valve 4 allows the gas mixture to be drawn out / discharged from tank 1.

[0062] In the subsequent fourth step, the second valve 5 can be opened. This opening is optional, as it is not required according to this embodiment. In the case of the simple valve 7, this valve must be opened. On the other hand, in the case of the check valve 6, it is automatically triggered to open by supplying new gas to the next stage.

[0063] The third and fourth steps can be performed in this order, simultaneously, or in reverse order.

[0064] In the subsequent fifth step, fresh pressurized gas is supplied through the outlet of the cleaning tool. This fresh gas is introduced into tank 1 via the second valve 5.

[0065] This allows the mixture of new and old gases to be discharged through the first valve 4. The gas mixture can then be recovered through the inlet of the cleaning tool.

[0066] The new gas delivery step is performed effectively while maintaining the predetermined cleaning time. This cleaning time is determined to achieve the desired final concentration of the new gas (or, equivalently, the residual concentration of the old gas).

[0067] This determination can be made in advance through testing or numerical simulation.

[0068] Alternatively, after maintaining the predetermined time period, a continuous supply of fresh gas can be made based on measurements of the actual concentration compared to the target concentration.

[0069] Once the target, time, and concentration have been considered to have been reached or the concentration has actually been reached, the first valve 4 is closed in the sixth step.

[0070] The supply of new gas is advantageously maintained until the desired gas pressure is reached in tank 1. Here, this pressure can be considered to have been reached after a predetermined time, or actually reached through servo control based on actual pressure measurements. This phase ends with the cessation of the supply of new gas.

[0071] The possible final step is to close the second valve 5. This is necessary in the case of the simple valve 7. This is unnecessary in the case of the check valve 6, which closes automatically when the pressure stops.

[0072] Compared to dilution cleaning methods, purging cleaning takes significantly less time. For example, dilution cleaning of a given tank takes 1919 seconds to achieve a residual concentration of 4% of the old gas, while purging cleaning of the same tank takes 53 seconds to achieve the same concentration. Dilution cleaning of the same tank takes 3755 seconds to achieve a residual concentration of 0.4% of the old gas, while purging cleaning of the same tank takes 100 seconds to achieve the same concentration.

[0073] When purging is performed according to the present invention, there are substantial advantages in terms of time and therefore cost.

[0074] The invention has been described in detail with reference to the accompanying drawings and the foregoing description. This should be considered illustrative and given by way of example, and not intended to limit the invention to this description alone. Many alternative embodiments may be adopted.

Claims

1. A diffuser (10) for a pressurized gas, such as pressurized hydrogen, in a container (1), characterized in that, The diffuser (10) is inside the tank (1) and is designed to inject pressurized gas.

2. The diffuser (10) according to claim 1, wherein the diffuser (10) extends through at least one channel (11) forming an angle (α) of less than 90° with the diffuser (10).

3. The diffuser (10) according to claim 2, wherein the at least one channel (11) comprises at least two channels (11) spaced equidistantly around the diffuser (10) at an angle.

4. The diffuser (10) according to claim 3, wherein the at least two channels (11) are not coplanar with the diffuser (10) so as to cause the injected gas to vortex.

5. The diffuser (10) according to any one of claims 2 to 4, wherein the at least one channel (11) is a 360° circle around the diffuser (10).

6. The diffuser (10) according to any one of claims 2 to 5, wherein the at least one channel (11) rotates about the diffuser (10).

7. A container (1) for pressurizing gases, such as pressurized hydrogen, characterized in that, The tank includes a diffuser (10) according to any one of the preceding claims.

8. The tank (1) according to the preceding claim, the tank comprising a first fluid device (2) and a second fluid device (3), the first fluid device comprising at least one first valve (4) adapted to allow the tank (1) to be evacuated, the second fluid device comprising at least one second valve (5) adapted to allow the tank (1) to be filled, wherein the second fluid device (2) comprises the diffuser (10).

9. The tank (1) according to the preceding two claims, wherein the first fluid device (2) is disposed at a first end (8) of the tank (1) and the second device (3) is disposed at a second end (9) of the tank (1) opposite to the first end (8).

10. A method for cleaning the tank (1) according to any one of the preceding three claims by means of a cleaning tool, characterized in that, The method includes the following steps: - Simultaneously or in any order, connect the outlet of the cleaning tool to the second valve (5) and the inlet of the cleaning tool to the first valve (4). - The first valve (4) may be opened simultaneously or in any order, and the second valve (5) may also be opened. - During the predetermined cleaning time, fresh pressurized gas is delivered through the outlet of the cleaning tool and discharged gas is recovered through the inlet of the cleaning tool. - Close the first valve (4), -When the desired gas pressure is reached in the tank (1), the gas supply is stopped. -Optionally close the second valve (5).

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