EP3374685A1

EP3374685A1 - Improved anti-static pressure tank

Info

Publication number: EP3374685A1
Application number: EP17826416.4A
Authority: EP
Inventors: Erfindernennung liegt noch nicht vor Die
Original assignee: Individual
Current assignee: Shubbar Abul Amir; SHUBBAR, MAHDI
Priority date: 2016-12-29
Filing date: 2017-12-13
Publication date: 2018-09-19
Anticipated expiration: 2037-12-13
Also published as: KR102439957B1; JP2020504800A; WO2018121812A1; DE102016125866A1; AU2017389266A1; BR112019013630A2; PH12019550104A1; CA3048293A1; KR20190099315A; PT3374685T; CN110312891B; AU2017389266B2; US20190346083A1; JP6987140B2; DE112017006695A5; US11226069B2; AR110688A1; SA518400698B1; EP3374685B1; CN110312891A

Abstract

Pressure tank for storing high- and low-pressure liquids/gases, in particular LPG or CNG, comprising a hollow body (1) made of a thermoplastic material having at least one opening (11) with a circumferential contact surface (111), a respective connection piece (2) per opening (11), which has at least one respective through-opening (21) to the interior (13) of the hollow body (1) and which is joined face to face with a complementary section (26) by the contact surface (111), wherein the through-opening (21) has a diffuser (22) at a lower end, which closes the through-opening (21) in the axial direction and has openings (221) only pointing substantially in the radial direction, and an anti-static wall (27) is provided surrounding the diffuser (22) inside the hollow body (1), wherein the anti-static wall (27) is part of the connection piece (2) or the collar ring (23) or is secured to the coupling part (3) as a separate part.

Description

Improved antistatic pressure tank

The present invention relates to a pressure tank for storing high and low pressure fluids / gases, in particular LPG or CNG, comprising a hollow body of thermoplastic

Plastic having at least one opening, which has a circumferential contact surface, one connection piece per opening, which has at least one passage to the interior of the hollow body and which is connected areally with a complementary portion with contact surface, wherein the passage at a lower

Having a diffuser, which closes the passage in the axial direction and has only substantially in the radial direction facing openings, in the interior of the hollow body, a diffuser enclosing the antistatic wall is present.

Tanks for holding gases or liquids under low or high pressure, e.g. liquefied petroleum gas (LPG) or compressed natural gas (CNG) are known in the art. These tanks are made, among other things, from thermoplastic synthetic material by blow molding, rotational molding or injection molding. In order to increase the pressure resistance, these tanks are provided in a second step with an outer layer of resilient fibers, which are usually embedded in a casting resin, which connects the fibers together and fixes them on the inner plastic layer.

Such a tank must be provided regardless of the design in any case with at least one fitting into which a pressure-tight coupling part in the form of a valve, hose or pipe end is used to fill the tank or empty. The connection between the connecting piece and the coupling part can be made via a latching plug or bayonet lock, but in high-pressure applications, for the most part

Screw caps with low thread pitch used.

The inner hollow vessel, also referred to as a liner, may in this case consist of metal, for example aluminum, titanium or steel, or, as mentioned above, be made of a plastic, for example a thermoplastic. The latter have the advantage that they are easier to mold and thus can be produced more cheaply and, moreover, their thermal expansion coefficients are better adapted to the matrix of the fiber-reinforced upper layer, which is usually a synthetic resin. The disadvantage, however, on the one hand a lower compressive strength compared to metallic liners same wall thickness, and a lower temperature resistance. Depending on the application, however, these disadvantages are behind the advantages listed above.

Another disadvantage of plastic liners, which is of primary importance for the present invention, is their low electrical conductivity and the concomitant tendency to charge statically when filling with a high pressure fluid. In this case, the fluid exits from the outlet opening of the filling valve, usually metal valve at high speed and travels with electrons, which then on impact on the inner

Vascular wall are deposited in the area of the impact site. Charge separation can furthermore be caused by the fluid jet impinging on the opposite side of the inner wall at high speed. With hollow bodies or liners made of metal or another conductive material, a charge compensation can take place quickly and easily. To further increase safety both hollow body / liner and valve can be grounded. With plastic fibers, such as thermoplastics, this is not or hardly possible or effective due to the poor electrical conductivity. The consequence is the static charge of the hollow body / liner, which literally can discharge in a flash and unpredictably. If there is still residual oxygen in the interior of the vessel, or if the filled fluid (mixture) is flammable, an explosion can occur. This problem occurs especially when filling an empty, dry pressure tank, since in this case the outflow of forming static charges can only take place poorly and also, if no previous inertization with inert gas has taken place, oxygen is present.

Two classes of solutions to this problem have hitherto been proposed in the prior art, which can be summarized under the heading remedies and avoidance. Both solutions are described by way of example in US Pat. No. 7,656,642 B2 (Ulekleiv et al.).

The solutions to remedy propose to improve the conductivity of the vessel inner wall, for example by a conductive coating of the otherwise hardly or hardly conductive plastic. This has the disadvantage that the advantage of the simpler and cheaper production of thermoplastic liners is at least partially canceled out. In addition, such a coating quickly wears away at highly loaded points of the hollow vessel inner wall, in particular at the point which lies opposite the inlet opening. The addition of antistatic additives is only conditionally applicable, as they have only a short-term effect. The avoidance strategy, on the other hand, attempts to establish the cause of the static charge, which in the high

Inflow velocity of the fluid can be seen from the valve. To reduce this, it is proposed to attach a diffuser at the lower end of the valve. This closes the passage in the axial direction and has only radially oriented openings, so that the inflowing fluid undergoes a directional deflection. As a result, it is braked on the one hand and does not strike the opposite inner wall as a bundled jet, but is split into several partial flows, which initially run horizontally without further measures and then deflected slightly under the influence of gravity almost tangentially onto the Inside wall would meet. In order to achieve a further reduction in speed, the abovementioned patent, however, proposes additionally enclosing the diffuser by a cylindrical collar formed as part of the liner / hollow body on the inside of the opening of the hollow body. The effluent from the radial openings of the diffuser fluid thus bounces against the collar and is thereby redirected again and strongly braked.

A disadvantage of this solution is that the extreme deceleration of the fluid through the circulating, closed collar leads to a full running of the remaining space between the diffuser and collar, so builds up a strong back pressure and thus the flow rate is greatly reduced. The flow in the intermediate space is very turbulent, so that there is a strong mechanical load on the adjacent components, diffuser, coupling part, fitting and collar, which contribute to a faster aging. However, a much more serious problem of the strong back pressure in the gap between the diffuser and the collar is that it causes the inflowing fluid to be pressed into the seam between the hollow body and the connection piece, which runs at the top of the intermediate space between the diffuser and the collar , which can be compromised especially at high filling pressures and rates, the tightness of the local pressure tank.

Since the wall thicknesses and the dimensional accuracy requirements for the connection pieces differ considerably from the wall thicknesses and the tolerances of the pressure tank, in practice it makes no sense nor is it economical to produce the connection pieces and the tanks in one piece.

Rather, it is customary to provide a hollow container made of plastic after its completion in a further operation with a separately manufactured and mostly multi-piece connector. Thus, e.g. the patent application US 201 1/010/1002 a tank made of plastic with two openings. On these openings, in each case from the inside and from the inside in each case an approximately cylindrical connection part is placed, which is widened at one end with a collar-shaped flange. These two parts are screwed together with a thread and thereby pressed together, so that they lie flat on the inside and outside of the area around the opening of the tank. By appropriate pressure as well as by additionally in the tank or the flanges embedded sealing rings the required pressure resistance is achieved.

Publication US 2014/0299610 A1 describes a pressure tank with a two-part connecting piece, in which an outer part made of a softer, more adaptable material blocks the connection. to the hollow vessel / liner and the fiber-reinforced layer resting thereon. In this outer connector, a second part is concentrically embedded, which provides a connection option to a valve or otherwise coupling part in the form of an internal thread. In order to withstand the forces that occur, this is made of a harder material. Between the inner part and a screwed valve there is a sealing lip of the connecting piece, which, in conjunction with one or more sealing rings surrounding the valve, ensures the tight fit of the valve even at high pressure.

This publication teaches to reduce the radial thickness of the sealing lip in proportion to the desired test pressure. However, this has the disadvantage that under high pressures under certain circumstances, the sealing lip is not able to compensate for the pressure-induced deformation of the valve, fitting and opening and in particular the sealing rings, which can cause leaks.

Against this background, the present invention has the task of developing a connector for pressure tanks made of plastic, which effectively prevents static charging, yet allows high filling rates and guaranteed absolute tightness even at high pressures.

As a solution, the invention teaches to provide an antistatic wall surrounding the diffuser which is formed as a part of the fitting or a neck ring or coupling part explained below. The tightness during filling is then ensured by the fact that the inevitable interface between the connector and the hollow body / liner advantageously outside of the filling with a high dynamic pressure loaded gap between diffuser and antistatic wall is positioned.

In an advantageous embodiment, a reduction in this dynamic pressure is achieved in that the antistatic wall and distributed over its circumference has a plurality of turbulator openings. Through this, the fluid flowing into the space between the diffuser at the lower end of the passage and the antistatic wall can leave the gap. This relieves the space left between the diffuser and the antistatic wall, thus providing a higher flow rate. By appropriate positioning of the turbulator openings relative to the radial openings of the diffuser, the turbulence of the flow can be further influenced. It makes sense to provide at least one turbulator opening in the antistatic wall per diffuser opening. These can each be aligned approximately with the associated diffuser opening. In this case, a high flow rate and a minimum turbulent flow in the region of the connector is achieved. In this case, the size of the turbulator opening is ideally chosen to be somewhat smaller than the beam cross section of the fluid emerging from the diffuser opening, wherein the beam expansion after leaving the diffuser opening is taken into account. This causes the flow to not be completely laminar, reducing charge separation by the flow.

Alternatively, it is proposed to align the diffuser openings with the solid webs between the turbulator openings in alignment. For a uniform as possible loading of the webs by the impinging force on them fluid, an alignment of the diffuser openings is preferred to the middle of the webs. In this relative arrangement, a strong deceleration similar to that of State of the art known continuous circumferential collar achieved, but with the decisive advantage that the inflowing fluid with the turbulator has a further outflow and forms a largely stationary flow in the space. The heavy material load of a highly turbulent flow is thus avoided and the build-up static back pressure is advantageously greatly reduced. Despite deceleration and double deflection of the inflowing fluid thereby the maximum possible flow rate is hardly reduced even with this orientation compared to a tank without diffuser (and / or antistatic wall). Outside and within the gap results in this arrangement, a sprinklerartiger effect in which the fluid atomized when hitting the webs of the antistatic wall with high force in fine to very fine droplets and then partially directly through the slot between the diffuser and webs fall down and partially finely distributed from the turbulator ports enters the outer tank volume. Thus, there is no longer a bundled fluid jet whose impact on the inner surface of the hollow body could cause further static charge.

If a material which conducts better conductivity than the liner material is used for the material of the connection piece, or if a nonconductive material is provided with a conductive coating, a further advantage of the teaching according to the invention results. This is related to the fact that the majority of the entrained by the flow in the valve or the coupling part charges, ie electrons, is already deposited on the antistatic wall. This is also the case with the pressure tanks known from the prior art. However, there is an effective charge backflow prevented by the execution of the collar as part of the non-conductive hollow body. at Manufacture of the connecting piece of conductive material is a charge return flow in the present invention by the integration of the antistatic wall in the connector readily possible.

It is thus an essential idea of the present invention to integrate the antistatic wall into the connection piece of the pressure tank, which ultimately serves for the (pressure-) stable connection of an actual coupling part for connection to fluid-carrying hoses or pipes with the hollow body including a possible fiber-reinforced cover layer , which bans the interface between the connector and the hollow body as a weak point from the space between the diffuser and antistatic wall, and achieve by introducing turbulator openings a largely stationary, less turbulent flow in the space, creating the build-up back pressure and thus the material load of this Reduced pressure exposed parts and the flow rate at given filling pressure is increased accordingly. The fluid is sprinkler-like atomized when hitting the webs of the antistatic wall or at the latest when exiting the constrictor turbulator openings and leaves the area of the gap as rain of fine and fine droplets that no longer have enough kinetic energy to impact on impact to effect a significant charge stripping on the hollow body inner wall or by friction in the air. The anti-static effect of the collar with turbulator openings according to the present invention is thus at least equal to that of a continuous collar, but avoids its massive disadvantages.

Further advantageous developments of the present invention, which can be implemented individually or in combination, provided they are not obviously mutually exclusive, will be presented and explained below.

The number of turbulator openings is preferably an integer multiple of the number of radial diffuser openings; in particular, the present invention proposes to provide the same number of turbulator and diffuser openings. Furthermore, the antistatic collar preferably has the same symmetries as the diffuser. Both diffuser and antistatic wall, including the turbulator openings, particularly preferably have an n-fold rotational symmetry with n> 2 and one

Mirror symmetry. This ensures that offset by the deflection of the flow on the fitting resulting forces and torques and the connection piece so in total force and torque is free.

The turbulator openings may be shaped differently, for example as round or oval openings in the antistatic wall. Preferably, however, they are designed as elongated recesses or notches starting at the lower edge of the wall and extending over a substantial part of their vertical extension, which have a width in the tangential direction which corresponds approximately to the diameter of the diffuser openings. This is firstly simple to manufacture and secondly results in a flow pattern of the inflowing fluid in the area of the connection piece, which represents a very good balance between turbulence and laminarity and, overall, a quasi-stationary flow. For further flow control, the lateral contour of the antistatic wall can be varied, for example, an additional waviness can be impressed on a round base contour, or else a polygonal basic shape is selected. Another way to favorably influence the flow conditions when filling the pressure tank is to impart a suitable topography to the inner end face of the diffuser on which the inflowing fluid impinges before exiting through the diffuser openings. This may, for example, be embodied as a convex or conical curvature opposite to the flow direction of the impinging fluid, which leads to improved pressure relief of the connection piece and higher flow rates.

In order to be able to ensure a safety against overpressure upon removal of fluid from the pressure tank, for example by breaking a line, a mechanism can be integrated in the diffuser, which closes the passage openings at excessively high flow rates.

An advantageous further development is further to form the antistatic wall as a separate part for attachment to the coupling part. This simplifies maintenance or replacement of the antistatic wall as a heavily loaded and thus wear-prone component. When using an antistatic wall without turbulator openings, which is subject to the highest loads due to impacting fluid, this simple serviceability represents a great advantage over designs according to the prior art in which the appropriate collar has an internal, integral component of the hollow body / liner represents.

Regardless of whether the antistatic wall is attached to the coupling part or embodied as part of the fitting or neck ring, various materials may be used to make it, to affect electrostatic or wear properties. Thus, in addition to a metal, for example, a thermoplastic material can also be used The connector of the pressure tank according to the invention is in the most common case in one piece, ie a coupling or connection option for valves, hoses or pipes or the like is integrated into the connector itself. This advantageously avoids additional contact or seams, which could endanger the tightness of the pressure tank. Due to the different requirements on the material properties of the connector in the region of contact with the hollow body, where it must be sufficiently resilient and elastic to adapt to the expansion of the hollow body under pressure load and thermal interference, and the region of the coupling to a fluid-carrying valve, a Hose or a pipe, where it must have sufficient strength and hardness, so as not to fatigue too quickly even with frequent coupling and uncoupling, but proposes an at least two-part design of the connector before present invention. Here, in an outer connection part made of softer, tougher material, in particular a material similar to the thermoplastic material of the hollow body and meltable by means of this connectable material, concentrically a second part, the so-called neck ring, of hard material, preferably metal, embedded, which has a valve or other coupling part via an internal thread or another coupling option. The neck ring is in this case pressed or cast in a complementary recess of the actual connection piece. Alternatively, the fitting is molded around the neck ring by casting or spraying.

The neck ring, in particular its contact surface with the actual connection piece, preferably has no circular symmetry, but only an n-fold rotation and particularly preferably one Mirror symmetry with a mirror plane containing the axial direction. The contact surface may, for example, have a polygonal, star or wavy outline. As a result, the contact area is increased and allows a better transfer of torque from the neck ring in the connector. In addition, the present invention proposes to discuss the scope of the

Neck ring or the circumferential collar or flanges distributes grooves and / or connecting holes, in which the liquid thermoplastic material of the connection piece can flow during manufacture. After cooling, a particularly stable, suitable for torque transmission connection is thus achieved. This is important in order to avoid any frequent changes, i. Screwing in and unscrewing a coupling part, the moments that occur could worsen the bond between the neck ring and actual fitting, which over time could lead to leakage to failure of the fitting.

The same applies to the forwarding of just mentioned torques from the connector in the hollow body. Therefore, the contact surface between the connector and the hollow body is also designed as a non-circularly symmetric torque clutch. Like the connecting surface from neck ring to fitting, a polygonal, star or wavy outline is also possible here. An alternative is to cast a thermoplastic hollow body around the fitting, whereby a particularly close connection and power transmission is guaranteed, especially when vertical holes are provided in the outer region of the connector into which flow the still liquid material of the hollow body and solidify there can. The disadvantage here is that the connector already be present during the production of the hollow body must and can not be changed without destroying it.

Therefore, present invention proposes particularly preferred to make the contact surfaces to the one or more fittings in the region of the opening (s) of the hollow body accessible from the outside, so that the connector after completion and curing of the hollow body, inserted and verscheißt and / or can be pressed. In particular, the axial cross-section of the opening should increase monotonically in the outward direction, in such a way that the axial projection of further outward-lying cross-sections further inward. If the connection part of the connection piece is made of thermoplastic material similar to the hollow body material, the connection can preferably take place by superficial melting of the contact surfaces and compression.

In the prior art, the diffuser is to the coupling part, i. the valve for connecting a hose or pipe, and in the most general case, the present invention also includes such a configuration. Preferably, however, the present invention proposes to integrate the diffuser, like the antistatic wall, in the actual connection piece. This has the background that usually in an internal thread of the connector or

Neck ring screwed coupling part is not always the same angular position relative to the antistatic wall occupies, but this varies at least a little with each screwing. As a result, the relative position of the diffuser openings to the turbulator openings is also not always the same, which can have a negative effect on the flow of the inflowing fluid. This variation of the relative position is advantageously avoided by integration of the diffuser into the fitting. The radially oriented diffuser openings are preferably round, oval or polygonal, in particular rectangular.

Another advantage of this solution results from the fact that conventional coupling parts are not equipped with a standard diffuser, but at the bottom of a simple, axially oriented inlet opening. Thus, by incorporating the diffuser into the actual fitting, despite the use of standard coupling parts, the present invention can take advantage of a high pressure fluid flow through the diffuser and antistatic wall.

The embedded in the actual connection part neck ring has preferably at the upper end of its passage opening on a centering bevel. During the manufacture of the connection piece, it ensures always identical positioning of the neck ring and the connection part, which is important because of the above-mentioned relative orientation of the turbo-torch and diffuser openings. This also facilitates the subsequent use of the rapid insertion and centering of coupling parts, especially if this is done automatically, such as by a placement robot.

Even more preferably, the neck ring has an axially downwardly projecting collar which is surrounded on its outer sides by the material of the fitting. As a result, on the one hand, the contact surface to the actual connection piece is further increased. On the other hand, the material of the connection piece which lies inwardly from the collar in the radial direction forms a sealing lip whose radial thickness has a decisive influence on the tightness of the pressure tank. Due to the finite vertical dimension of the connection piece, the opening with inserted connection piece projects slightly into the interior of the hollow body. The internal tank pressure now acts on both the outer and the inner side of this toroidal emphasis, the inner side is formed depending on the embodiment with or without integrated diffuser through the coupling part or the lower part of the connector. As a result, the material of the connecting piece and in particular the sealing lip is compressed. Furthermore, by the pressure in the tank, fluid or gas is pressed into the gap between a sealing ring of a coupling part and the sealing lip, deforming both the sealing ring and the sealing lip until an equilibrium of forces between the stresses in the sealing ring, the sealing lip and the internal tank pressure is achieved.

If the radial thickness of the sealing lip is not sufficiently dimensioned, leakage occurs at the connection between the actual connecting piece and the neck ring or connecting piece and coupling part. The latter can be avoided by using a sealing ring between the coupling part and the sealing lip. The hardness of this sealing ring should increase with the test pressure of the tank, and thus also the intended maximum filling pressure.

The present invention therefore proposes to make the radial thickness of the sealing lip larger with the intended test pressure of the pressure tank according to the invention. Specifically, it is proposed to increase the thickness of the sealing lip in proportion to the test pressure. In experiments it was found that a change according to the relationships

Dmax [mm] = 0.01 F [bar] + 3.0 optimal tightness guaranteed. Here, P denotes the test pressure, and Dmin the lower and the Dmax the upper limit of the preferred radial sealing lip thickness D. The use of a sealing ring between the sealing lip and coupling part with a Shore hardness of at least 90 was assumed.

An alternative method of sealing between fitting and valve, which is used in the prior art in particular for pressure tanks with hollow steel body made of steel, consists in the use of valves with conical, downwardly tapering, external thread. The resulting metallic seal, supported in common practice by a viscous sealant, makes the use of a sealing ring superfluous. In an advantageous variant of the invention, the connection of such a conical valve is provided by suitable design of the neck ring. In particular, the design of the connector is addressed without diffuser, since conical valves are already equipped in the most common design with a diffuser, but without anti-static wall. In order to be able to set the relative position of diffuser and turbulator openings specifically in this connection variant, it is proposed to provide suitable markings on the connection piece and the valve, which designate the position of the openings.

In order to withstand very high test pressures of several hundred to over one thousand bar, the hollow body of the pressure tank according to the invention must be enclosed by a fiber-reinforced cover layer. This is all the more necessary, since the thermoplastic materials proposed for the hollow body could withstand only a few bar up to a maximum of about ten bar on their own with typical wall thicknesses in the millimeter range. The fibers used in this layer can be synthetic fibers, such as Glass, carbon, aramid, dyneema or other synthetic fibers, or natural fibers. Various fiber species can also be used in combination to optimize costs at a desired strength. The matrix in which these fibers are embedded consists of either thermally or optically crosslinked

(Art) resins such as epoxy resin, or of a plastic, for example polyethylene, which is applied in liquid form to the fiber-wound hollow body and then allowed to cool. Particularly preferably, the outer side of the hollow body before the winding of the fibers and the application of the surrounding matrix is subjected to a surface treatment in which the roughness increases and thus a better connection between matrix layer and liner / hollow body is achieved.

In the following, further details and features of the invention will be explained in more detail with reference to the embodiments explained with reference to the figures. However, these are not intended to limit the invention, but only to explain.

It shows in a schematic representation:

Figure 1: Cross-section through an embodiment of the pressure tank according to the invention with anti-static wall with turbulator ports on the connector and in a coupling part integrated diffuser

FIG. 1 a: enlarged detail of the lower half of the connecting piece from FIG. 1

Figure 2: Perspective view obliquely from below on the

Connector of Figure 1

Figure 3: Perspective view obliquely from below and cutaway view of another embodiment of the connector with integrated diffuser. Figure 4: relationship between test pressure and sealing lip thickness in the radial direction

Figure 5: cross-section of another embodiment of the connector with profiled diffuser Stirnf laugh

Figure 6 shows a cross section of a further embodiment of the connection piece and coupling part with the latter associated anti-static wall and diffuser

Figure 7 Perspective view obliquely from below on another embodiment of the coupling part with antistatic wall and diffuser

FIG. 8: a cross-section of a further embodiment of the connecting piece with overpressure safety device integrated in the diffuser (in the closed position)

8a shows a cross section through the connecting piece from FIG. 8 with the overpressure safety device opened

FIG. 1 shows a cross section through an opening with inserted connection part of a pressure tank according to the invention. Connector 2 is fixedly inserted into opening 1 1, wherein the mutually complementary contact surfaces 26 and 1 1 1 a torque clutch for uniform and effective transmission of torque from the connector 2 on the hollow body. 1 Another torque coupling is covered by the contact surfaces between the connection part 20 of the connection piece 2 and the fiber-reinforced layer 8, which hollow body 1 and partial connection part 20. Connecting piece 2 is in two parts and consists of the outer connecting part 20 and in this embedded neck ring 23, which has an internal thread 25, by means of which coupling part 3 is screwed into the connecting piece 2. The handling and positioning of coupling part 3 in the manufacture, in particular, if it is done automatically by a loading robot, is characterized by the Centering bevel 234 facilitates at the upper end of the internal thread 25. At the lower end of the passage opening 21 diffuser 22 is integrated in the coupling part 3.

Diffuser 22 serves to slow down and redirect a fluid flowing in under high pressure, for which purpose it closes openings 21 in the axial direction and only has radially oriented outlet openings 221. The radially flowing after passing through diffuser openings 221 fluid hits with respect to a theoretical flow velocity without diffuser reduced speed on the diffuser 22 enclosing antistatic wall 27, which is formed as turbulator openings 28, here formed as elongated notches, interrupted cylinder collar. Antistatic wall 27 is an axially directed projection of the outer connector 20 and thus constitutes an integral part of the connecting part 20. In order for the coupling part remains free of forces and torque during filling, the diffuser 2 are mirror-symmetrical and rotationally symmetrical, where he 6 having no rotational symmetry. The same applies to antistatic wall 27.

As a result, a substantial improvement of the present invention is ensured, namely that the seam 12 between the hollow body 1 and fitting 2 is located outside the space between the diffuser 22 and the antistatic wall 27. This advantageously prevents the fluid flowing in under high pressure from being forced into the seam by the high static counter-pressure building up in said intermediate space, possibly in conjunction with the dynamic pressure of the fluid impinging on the boundary surface of the intermediate space, and thus the tightness the pressure tank when filling or even in the worst case plastic deformation, permanently compromised. This is promoted by the fact that only a small back pressure builds up in said gap, since the turbulator openings 28 provide an additional drainage path. The fluid is thereby atomized as it passes through the openings 28 in a mist of fine droplets, which minimizes the risk of static charge further away from opening 1 1 lying areas.

The tightness of the pressure tank according to the invention shown here both in the filling and in the pressure-filled state is further advantageous by dimensioning the radial thickness of the sealing lip 24, which extends between a down in the axial direction from the neck ring 23, starting neck collar 231 and sealing ring 31 of the Coupling part 3 extends, proportionally increasing with the intended test pressure, ie Maximum pressure of the tank guaranteed.

FIG. 1a shows an enlarged section of the lower half of connecting piece 2 and of the lower end of passage 21, respectively. The difference between the height HT of the internal thread 25 and the distance DO between the lower edge of internal thread 25 and sealing ring 31 is selected according to the relationship HT-DO <0.5 TP, where TP stands for the thread pitch of the internal thread 25.

Figure 2 shows a perspective view obliquely from below of the connector of Figure 1. The hexagonal shaped contact surface 26, which with the complementary contact surface of the opening of the hollow body, in which connector 2 is inserted and welded or glued, a torque clutch for transmission of torques of fitting 2 forms on the hollow body of the pressure tank. Into the internal thread of the, not visible Ren, neck ring 23 is screwed coupling part 3, which has at its lower end on the flow in the axial direction a flow-forming diffuser 22. Coupling part 3 is screwed in so far that the radially oriented diffuser openings 221 are aligned approximately with turbulator openings 28 in antistatic wall 27. As a result, a high flow rate is achieved during filling, but at the same time, achieved by the corresponding narrow dimensioning of the turbulator openings 28 in width, a still good antistatic effect. However, this is optimized if the diffuser openings 221 are not aligned with the turbulator openings 28, but face the continuous collar 27, so that from the openings 221 exiting fluid impinges on these and is further decelerated. In this case, almost all of the coupling part 3 or diffuser 22 entrained charges in antistatic wall 27 are deposited, from where they are derived by droplets to the coupling part 3 and diffuser 22, since collar 27 part of, relatively leitfähiger shapable, connecting part 2 and not of, non-conductive, hollow body 1 is.

FIG. 3 shows a further preferred embodiment of the connection part of the pressure tank according to the invention.

The upper part of the figure shows a perspective view obliquely from below, which shows that diffuser openings 221 are aligned relative to the antistatic wall 27 with turbulator openings 28 so that a fluid jet emerging from the openings 221 hits the solid wall sections 27 exactly in the middle. As in the embodiment shown in FIGS. 1-2, diffuser 22 is mirror-symmetric and six-fold rotationally symmetric.

The lower part of the figure shows a cutaway view of the connector 2. As you can see, this is also a two-part rem fitting 20 and neck ring 23 constructed. Neck ring 25 in turn has an internal thread 25 for connecting a hose, pipe or a valve or other coupling part. The essential difference from the previous embodiment is that diffuser 22, as clearly seen in this subfigure, is an integral part of fitting 2, more specifically fitting 20. This avoids a potentially different relative orientation of the diffuser openings 221 to the antistatic wall 27 and the turbulator openings 28 during each screwing operation.

FIG. 4 shows in a graph the relationship proposed by the present invention between the radial thickness D of the sealing lip 24 and the desired test pressure. The sealing lip thickness is here plotted on the y-axis, the pressure on the x-axis. The gradient is linearly monotonously increasing with a proportionality constant (slope) of 0.01 mm / bar in the case of the maximum recommended thickness Dmax and 0.019 mm / bar in the case of the minimum recommended thickness Dmin. The respective intercepts at 100 bar are 3.03 mm and 4.0 mm respectively with minimum and maximum recommended thickness. The radial thickness D should therefore be between Dmin and Dmax for given test pressure P in order to guarantee optimum tightness.

FIG. 5 shows a further advantageous embodiment of the connecting piece 2 of the pressure tank according to the invention, which, in order to modify the flow conditions on the inner end face 222 of the diffuser, has a frusto-conical protrusion opposite to the direction of flow of the fluid. The lateral Halsringflansch 232 serves to support the neck ring 23 under axial load. In it are embedded neck ring holes 233, in which the liquid thermoplastic material of the connector can flow during manufacture.

FIG. 6 shows an embodiment in which both the diffuser 22 and the antistatic wall 27 form part of the coupling part 3. This offers the special advantage that the antistatic wall 27 can be made easily accessible as highly loaded component maintenance or replacement measures in which the coupling part 3 is removed.

FIG. 7 illustrates an embodiment of the antistatic wall 27 and the diffuser 22, in which the turbulator openings 28 of the antistatic wall 27 are radially tapered and have a polygonal contour. Such formations of the turbulator openings and expedient contours on the inner surface of the antistatic wall 27 facing the diffuser 22 represent a possibility for guiding the flow of fluid in detail and also for influencing the material wear of the antistatic wall 27 itself.

Figure 8 shows an embodiment of the diffuser 22 with integrated overpressure protection 9, which is here in the closed position. A complementary representation of the overpressure safety device 9 in the open position is given in FIG. 8a. In the event of a sudden pressure drop on the outlet side and thus a rise in flow during the flow, for example due to the bursting of a pipe, the overpressure safety device is entrained and closes the outlet above the diffuser openings 221. LIST OF REFERENCE NUMBERS

1 hollow body

1 1 opening in the hollow body 1

1 1 1 contact area

12 interface between the hollow body and fitting

13 interior of the hollow body

2 connection piece

20 connection part

21 passage opening

22 diffuser

221 diffuser opening

222 inner diffuser end face with bulge

23 neck ring

231 neck collar

232 neck flange

233 neck ring holes

234 centering bevel

24 sealing lip

25 internal thread

26 contact surface

27 antistatic wall

271 internal antistatic wall surface

28 Turbulator opening

3 coupling part

31 sealing ring

8 fiber reinforced layer

81 torque clutch

9 overpressure protection P test pressure

D Sealing lip thickness, radial

Dmin minimum recommended sealing lip thickness Dmax maximum recommended sealing lip thickness

TP thread pitch

HT thread height

DO sealing ring distance to the threaded lower edge

Claims

claims

1 . Pressure tank for storing high and low pressure fluids / gases, in particular LPG or CNG, comprising

- A hollow body (1) made of thermoplastic material having at least one opening (1 1), which has a circumferential contact surface (1 1 1),

- One connecting piece (2) per opening (1 1), which has at least one respective passage (21) to the interior (13) of the hollow body (1) and with a complementary portion (26) with contact surface (1 1 1) surface wherein the passage (21) has at a lower end a diffuser (22), which may be part of the connecting piece (2) or a neck ring (23) or a coupling part (3), and which the Durchläse (21 ) closes in the axial direction and has only substantially radially pointing openings (221),

inside the hollow body (1), an antistatic wall (27) enclosing the diffuser (22),

characterized in that

the antistatic wall (27) is a part of the fitting (2) or the neck ring (23) or is attached as a separate part to the coupling part (3)

2. Pressure tank according to claim 1, characterized in that the antistatic wall (27) has a plurality of turbulator openings (28) which are positioned relative to the diffuser openings (221), in that pressurized fluid forms a substantially stationary flow in the region below the connecting piece (2).

Pressure tank according to claim 2, characterized in that the turbulator openings (28)

- are elongated recesses which extend at the bottom of the antistatic wall (27) starting over a substantial part of their height, and / or

- Are arranged in alignment with the radial openings (221) of the diffuser (22), or

- The continuous sections of the antistatic wall (27) opposite, in particular with their respective center are arranged in alignment.

A pressure tank according to any one of the preceding claims, characterized in that the antistatic wall (27) has a round contour along its surface (271) facing the diffuser (22) or has a more complex contour, e.g. a wavy contour or a polygonal contour.

Pressure tank according to one of the preceding claims, characterized in that the diffuser (22) - Has round, oval or polygonal, in particular rectangular diffuser openings (221), or

- Has an inner end face (222) which is flat or has a more complex topography, in particular a convex or conical protrusion, or

- Is equipped with a mechanism (9) which closes the passage (21) at a critical flow rate of the fluid.

6. Pressure tank according to one of the preceding claims, characterized in that the passage opening (21) of the connecting piece (2) has an internal thread (25) into which a valve or other coupling part (3) is screwed, which for the purpose of sealing

- Has at least one sealing ring (31), or

- Has a conical external thread.

7. Pressure tank according to one of the preceding claims, characterized in that the connecting piece (2) comprises a pressed or cast neck ring (23) which is concentrically located in an outer connection part (20) of the connecting piece (2) and at least part of the passage opening (21) and the internal thread (25).

8. Pressure tank according to claim 7, characterized in that the neck ring (23) - With respect to rotation about the axial direction of the aperture (21) has a relation to the circular symmetry reduced symmetry, in particular an n-fold rotational symmetry, for example a polygonal cross-section, or has no symmetry, and / or

a mirror symmetry with a mirror plane containing the axial direction, and / or

- A projecting in the radial direction, circumferential collar (232) with openings therein (233), and / or

- At the upper end of the opening (21) has a Zentrierfase (234), and / or

- Made of metal and / or

- Is provided with connecting holes and notches.

Pressure tank according to claim 7 or 8, characterized in that the connection part (20)

- Is made of a thermoplastic material, and

- Contact surface (26), with which it is attached to the complementary contact surface (1 1 1) of opening (1 1) in the hollow body (1) surface, in particular, by pressing, gluing or welding by superficial liquefaction of the thermoplastic materials of the contact surfaces (1 1 1) and (26) and then pressed together.

10. Pressure tank according to one of claims 7-9, characterized in that the neck ring (23) on the underside a downwardly facing, the passage opening (21) enclosing neck collar (231) which is surrounded on its outer sides by the material of the connection part (20), so that the material of connection piece (2) located between the inside of the neck collar (231) and the passage opening (21) forms a sealing lip (24).

1 1. Pressure tank according to claim 10, characterized in that

at least one sealing ring (31) between the coupling part (3) and sealing lip (24).

12. Pressure tank according to claim 10 or 1 1, characterized in that a radial thickness of the sealing lip (24) is selected in proportion to a test pressure of the pressure tank (1).

13. A pressure tank according to any one of claims 10-12, characterized in that the radial thickness of the sealing lip (24) between a minimum thickness (Dmin) and maximum thickness (Dmax) is selected, these thicknesses with the test pressure (P) on the Relationships

Dmax [mm] = 0.01 P f & ar] -f- 3.0

Dmin {mm] = 0.019 Dmax [mm] -f- 2.95

related.

14. Pressure tank according to one of the preceding claims, characterized in that the contact surfaces (26, 1 1 1) for transmitting torque from the connecting piece (2) on the hollow body (1) as a torque clutch with respect to rotation about the axial direction of the passage (21 ) is not circularly symmetrical and in particular which has an n-fold rotational symmetry, for example a polygonal outline.

15. Pressure tank according to one of the preceding claims, characterized in that on the hollow body (1) rests another layer (8) which is reinforced by fibers, in particular glass fibers, carbon fibers, aramid fibers, Dyneema fibers, other synthetic fibers and / or natural fibers and further a matrix enclosing the fibers, in particular of thermally or ultraviolet crosslinkable resins or other resins, wherein in particular before the application of the reinforcing layer a prior surface treatment of the outside of the hollow body (1) has taken place.

16. A pressure tank according to claim 15, characterized in that in the region of the opening (1 1) in the fiber-reinforced layer (8), a second torque clutch (81) is formed, which for the purpose of dissipation to the connecting piece (2) acting torques in the Layer (8) has a non-circularly symmetrical shape, in particular with n-fold rotational symmetry or a polygonal shape.

17. Pressure tank according to one of claims 6-16, characterized in that the difference between a height (HT) of the internal thread (25) and the axial distance between a lower edge of the internal thread (25) and the center of the sealing ring (31) of relation

HT fmm] - DO fmm] <Q _t S TP

obeys, and on (TP) denotes a thread pitch of the internal thread (25) in millimeters per turn and n _T denotes the number of turns of the internal thread (25).