Base for pressurized gas tank, with improved sealing

Abstract

Pressurized gas tank base with improved sealing. The base (16) has a general shape of revolution about a base axis and includes an annular extension (24) having an annular inner face (25) substantially perpendicular to the base axis. The annular inner face (25) has radial grooves (36) for receiving projecting ribs of an inner tank lining. (See Figure 2 for abbreviations)

Description

Title of the invention: Pressurized gas tank base with improved sealing

[0001] The present invention relates to a base for a pressurized gas tank, in particular hydrogen, for example intended to equip a motor vehicle.

[0002] A pressurized gas tank is already known in the state of the art, comprising a base, and an internal coating connected to this base, for example overmolded onto this base.

[0003] In order to ensure optimal operation, the base must be able to withstand high pressures (at least 700 bars), emptying / filling cycles, and strong temperature variations (for example from -40°C to 85°C).

[0004] The aim of the invention is then to propose a gas tank with improved sealing, allowing the base to ensure good sealing even under the conditions mentioned above.

[0005] To this end, the invention relates to a high-pressure gas tank base, having a general shape of revolution around a base axis, and comprising an annular extension having an annular inner face substantially perpendicular to the base axis, characterized in that the annular inner face comprises radial grooves intended to receive projecting ribs of an inner lining of the tank.

[0006] According to other advantageous aspects of the invention, the tank comprises one or more of the following characteristics, taken individually or in all technically possible combinations:

[0007] - The radial grooves are each defined by two walls parallel to each other, extending radially in length from the base axis, the walls defining a right angle with the annular inner surface.

[0008] - The radial grooves are each defined by two walls parallel to each other, extending radially in length from the base axis, the walls defining a non-right angle with the annular inner surface.

[0009] - The grooves are arranged in pairs of adjacent grooves, the walls of each groove of each pair being convergent towards the walls of the other groove of the pair.

[0010] - The grooves are arranged in pairs of adjacent grooves, the walls of each groove of each pair being divergent with respect to the walls of the other groove of the pair.

[0011] - The angles formed between the walls of each groove of the pair with respect to the face interior are opposed.

[0012] - Each wall of each groove forms with the inner face an angle included between 60 and 90°, preferably between 70 and 80°, advantageously substantially equal to 75°, or between -60° and -90°, preferably between -70 and -80°, advantageously substantially equal to -75°.

[0013] The invention also relates to a tank for pressurized gas, characterized in that it comprises a base as defined above, and an internal coating comprising an annular extension comprising projecting ribs engaged in the radial grooves.

[0014] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0015] [Fig-1] [Fig.l] is a partial perspective view of a tank according to an example of an embodiment of the invention, cut longitudinally on the one hand, and cut transversely along the axis of its base on the other hand;

[0016] [Fig.2] [Fig.2] is a perspective view of a base of the tank of [Fig.l];

[0017] [Fig.3] [Fig.3] is a side view of the base of [Fig.2].

[0018] [Fig. 1] shows a reservoir 10 of pressurized gas, in particular hydrogen, for example intended to equip a motor vehicle.

[0019] For example, the tank 10 is of type IV (i.e. a composite tank with a polymer liner) and conformable, prismatic in shape and manufactured in two parts.

[0020] The tank 10 comprises a composite casing 12, enveloping an interior coating 14. The interior coating 14 is for example made of thermoplastic polymer.

[0021] The inner coating 14 has, for example, a general shape of revolution around a longitudinal axis X of the tank 10. It will be noted, however, that any other shape of tank 10 is conceivable.

[0022] The reservoir 10 also comprises a base 16, passing through the casing 12 and the covering 14.

[0023] The base is for example made of aluminum.

[0024] The base 16 extends along a base axis Y. In the example described, the base axis Y is perpendicular to the longitudinal axis X. Indeed, in this example, the base 16 is arranged on a side wall of the covering 14.

[0025] According to a variant, the base axis is aligned with the longitudinal axis X, the base being arranged at a longitudinal end of the tank.

[0026] The base 16 has a central opening 18 extending along the base axis Y over the entire length of the base 16, allowing communication between the inside and the outside of the tank. The filling and emptying of the tank are carried out through this central opening 18. For this purpose, a tank valve (not shown) is arranged in a conventional manner on an outer end of the base 16.

[0027] The base 16 comprises an outer tubular part 20, extending outside the space delimited by the inner coating 14, and more particularly the space delimited by the casing 12. The base also comprises an inner tubular part in two parts of different outer diameters, called first inner tubular part 22a and second inner tubular part 22b, extending inside the space delimited by the inner coating 14.

[0028] The base 16 comprises an annular extension 24 extending radially relative to the base axis Y, and located longitudinally, in the direction of the base axis Y, between the outer tubular part 20 and the inner tubular part 22a, 22b.

[0029] The first inner tubular part 22a is arranged longitudinally, in the direction of the base axis Y, between the annular extension 24 and the second inner tubular part 22b.

[0030] The first inner tubular portion 22a has an external diameter greater than that of the second inner tubular portion 22b. A shoulder 26 is provided between the first inner tubular portion 22a and the second inner tubular portion 22b.

[0031] The external surface of the second inner tubular part 22b is threaded, in order to allow the screwing of a tightening nut 28.

[0032] A sealing ring 30 is arranged longitudinally, in the direction of the base axis Y, between the annular extension 24 and the clamping nut 28.

[0033] The sealing ring 30 comprises a first ring portion 30a surrounding the first inner tubular portion 22a, and a second ring portion 30b surrounding the second inner tubular portion 22b.

[0034] An O-ring seal 31 is arranged radially between the first ring portion 30a and the first inner tubular portion 22a.

[0035] The second ring part 30b is arranged longitudinally, in the direction of the base axis Y, between the shoulder 26 and the clamping nut 28.

[0036] The inner coating 14 comprises an annular portion 32, resting on an annular inner face 25 of the annular extension 24 of the base 16. The annular inner face 25 is preferably substantially perpendicular to the base axis Y.

[0037] Generally, this annular part 32 is overmolded onto this inner face 25 of the annular extension 24. For this purpose, the inner face 25 is shaped for good adhesion of the annular part 32, as will be described later with reference to FIGS. 2 and 3.

[0038] The reservoir 10 according to the invention comprises a circular seal 34 compressed longitudinally between the sealing ring 30 and the annular part 32. As a variant, the circular seal 34 is toric, and arranged in a groove made in the sealing ring 30.

[0039] Thus, when the tightening nut 28 is screwed, the second ring part 30b comes to bear against the shoulder 26, while the first ring part 30a compresses the circular flat seal 34 on the annular part 32.

[0040] The sealing of the tank is therefore ensured by the circular flat seal 34 between the sealing ring 30 and the annular part 32, and by the O-ring between the sealing ring 30 and the base 16.

[0041] As shown in [Fig. 2], the inner face 25 of the annular extension 24 comprises radial grooves 36 intended to receive projecting ribs of the annular part 32 of the inner coating 14. These projecting ribs are produced during the overmolding (for example by injection process) of the annular part 32 on the inner face 25.

[0042] Each radial groove 36 is defined by two walls 38 parallel to each other. The walls 38 of each groove 36 are preferably inclined relative to the base axis Y, that is to say they preferably form a non-right angle with the inner face 25.

[0043] In the example shown, the grooves 36 are arranged in pairs of adjacent grooves, their walls 38 of the grooves of the pair being inclined so that the walls of each groove of the pair converge towards the walls of the other groove, in a direction starting from the outside towards the inside of the reservoir 10.

[0044] In other words, each wall of each groove converges from the bottom of the groove towards a direction parallel to the base axis Y.

[0045] [Fig.3] shows a profile view, in a first plane parallel to the base axis Y and perpendicular to a second plane passing through the base axis Y and passing between the two grooves of the pair, at equal distance between these grooves.

[0046] In this first plane, the walls 38 form a non-right angle with the inner face 25. The angles formed by the walls 36 of the two grooves 36 are preferably opposite from one groove to the other. Thus, the two grooves 36 are symmetrical to each other with respect to the second plane.

[0047] The angle is preferably between 60° and 90° (exclusive) for one of the grooves of the pair, and between -60° and -90° (exclusive) for the other groove of the pair.

[0048] Preferably, each wall 38 of each groove 36 forms with the inner face 25 an angle of between 60 and 90°, preferably between 70 and 80°, advantageously substantially equal to 75°, or of between -60° and -90°, preferably between -70 and -80°, advantageously substantially equal to -75°.

[0049] In other words, each wall 38 forms an angle with said second plane passing through the base axis Y, preferably between 0° and 30° for one, and between 0° and -30° for the other, the two angles being opposite. Preferably, these angles are between 10 and 20°, advantageously substantially equal to 15°, for one, and between -10° and -20°, advantageously substantially equal to -15° for the other.

[0050] In [Fig.3], the angles are 15° and -15°, so that the angle between the two walls is 30°.

[0051] The angles of the walls 38 of the grooves 36 allow better grip of the annular part of the coating, which makes it possible to improve the sealing of the interface between the inner face 25 and the coating 14. In addition, these wall angles make it possible to ensure toric resistance of the base when tightening the tank valve.

[0052] It will be noted that as a variant, the walls of the two grooves could diverge from each other from the bottom of the grooves, towards the inside of the tank.

[0053] In another variant, the walls could form a right angle with the annular inner surface 25.

Claims

Claims

1. Base (16) of a high-pressure gas tank (10), having a general shape of revolution around a base axis (Y), and comprising an annular extension (24) having an annular inner face (25) substantially perpendicular to the base axis (Y), in which the annular inner face (25) comprises radial grooves (36) intended to receive projecting ribs of an inner lining (14) of the tank (10), characterized in that: - the radial grooves (36) are each defined by two walls (38) parallel to each other, extending in length radially from the base axis (Y), the walls (38) defining a non-right angle with the annular inner surface (25) - the grooves (36) are arranged in pairs of adjacent grooves, - the walls (38) of each groove (36) of each pair are convergent towards the walls (38) of the other groove (36) of the pair,or divergent with respect to the walls (38) of the other groove (36) of the pair, and - the angles formed between the walls (38) of each groove (36) of the pair with respect to the inner face (25) are opposite.,

2. Base (16) according to claim 1, in which each wall (38) of each groove (36) forms with the inner face (25) an angle of between 60 and 90°, preferably between 70 and 80°, advantageously substantially equal to 75°, or of between -60° and -90°, preferably between -70 and -80°, advantageously substantially equal to -75°.

3. Tank (10) for pressurized gas, characterized in that it comprises a base (16) according to any one of the preceding claims, and an internal coating (14) comprising an annular extension (32) comprising projecting ribs engaged in the radial grooves (36).

Images