Tank fitting for flexible tanks

Abstract

Tank fitting for flexible tanks, consisting of a flange part (16) and a removable cover (17), characterized in that it consists of a flange part (16) which is positively connected to the bag wall.

Description

[0001] Modern liquid containers, e.g., for holding fuel or other liquids, are often made of flexible materials. Such tanks are made of plastic composite films. Their primary advantage is that they contract during the liquid withdrawal. They can be emptied completely and without bubbles, provided the initial filling was carried out without air and the filling valve is subsequently closed. Bubble-free fuel withdrawal is particularly important in model aircraft with turbine engines. Such engines are very sensitive to air pockets in the fuel.

[0002] Another advantage of such flexible tanks (hereinafter referred to as "bag tanks") is their comparatively low weight. They also allow for better space utilization in limited tank spaces.

[0003] The current manufacturing technique involves placing at least two layers of composite film on top of each other and sealing them with circumferential heat-sealed seams. A bag tank manufactured this way is flat when empty and pillow-shaped when filled. More complex manufacturing and welding techniques also allow for cylindrical, cuboid, or geometrically undefined tank shapes.

[0004] To enable filling or emptying of such tanks, hose feedthroughs through the tank wall are required, and these must be absolutely leak-proof. According to the current state of the art, so-called hose nipples or screw nipples are inserted through holes previously made in the bag wall and screwed to the bag wall using sealing washers, O-rings, and nuts. The hose nipples accommodate hoses on both sides. At least one hose inside the tank accommodates a so-called tank pendulum. According to the current state of the art, the hose nipples are either straight or angled. Straight screw nipples accommodate hoses at right angles to the tank wall. They have the disadvantage that they extend far into the tank. Angled screw nipples do not extend as far into the bag tank and accommodate the hose located in the bag tank at right angles (parallel to the tank wall). The previously mentioned hose feedthroughs, based on the current state of the art, have several disadvantages. 1. The hose nipples and internal elements (hoses, tank pendulum) must be incorporated before the final weld seam seals the bag. This significantly complicates the subsequent manufacturing process, as the bag should ideally be flat during the welding process. 2. All connection nipples, tank hoses and tank filters inside the tank must be absolutely tight before closing the tank and the required hose diameters (flow rates) must be finally determined, as later changes are no longer possible. 3. A component inside the bag tank that is later damaged due to wear or contamination can no longer be replaced without destroying the bag. 4. State-of-the-art straight hose feedthroughs are designed to be very high. The hose, which is pushed inside the bag tank, adds to the rigidity. This, firstly, makes it difficult to remove the filling medium completely when the bag tank empties or contracts. Secondly, it leads to increased wrinkling and buckling of the film walls. 5. The angled hose feedthroughs according to the current state of the art lead the internal hose parallel to the tank wall, which is not ideal, since the tank pendulum connected to this hose should point towards the center of the tank. 6. The hose nipples used today, according to the state of the art, have a very small flange footprint. Frequent filling and emptying of the tank leads to buckling stress on the tank's foil wall, which causes material fatigue and shortens its service life. 7. The restriction listed under 1. requires multiple work steps at one workstation and does not allow interruptions in the production process. This makes a division of labor approach impossible. 8. The plastic sealing washers and O-rings that are essential for passing through a very thin film wall represent additional purchased parts that also double the risk of leaks. 9. The filled tank must always be vented at the highest point. However, the hose nipples used today extend into the bag, making it difficult to completely remove all the air.

[0005] To overcome the disadvantages of tanks manufactured using current technology, the aim was to create a tank fitting that could be easily inserted into the bag tank. One that does not extend far into the tank and has a removable cover that accommodates all hose feedthroughs. The cover was to be located above the tank to prevent hoses from kinking and to facilitate the extraction of residual air from the tank. Its main function, however, was to enable damaged or contaminated parts inside the tank to be replaced at a later date without destroying the tank. A flange base that does not extend far into the tank is intended to enable the work steps for a division of labor in production. To reduce manufacturing costs, it was also necessary to provide access to inexpensive basic components and to reduce the number of sealing washers.

[0006] The problems of tanks manufactured according to the current state of the art are solved by the features of a tank fitting for flexible tanks listed in the claims. This enables simpler and more cost-effective production. Further advantages of the invention lie in the exclusion of the problems listed under points 2, 3, 4, 5, 6 and 9. The novel principle of the invention consists in the use of a novel tank fitting consisting of a flange part with a removable cover. The flange part is firmly connected to the bag using the novel connection type according to the invention, while the removable cover serves to accommodate components necessary for withdrawing the liquid. The flange part has a sufficiently large diameter to allow hoses and filter elements to be passed through its neck. The base part of the flange is very flat and therefore does not build up inside the bag tank.The neck of the flange, which lies outside the bag tank, accommodates a removable lid, which can be screwed on, for example. The removable lid accommodates the elements listed under 1. The hose nipples are now no longer screwed through a thin film wall as before, but through a removable lid. The wall of this lid is sufficiently thick to seal hose nipples or other feedthroughs against the lid without O-rings and plastic sealing washers. The flange leading through the bag wall has at least one constriction in its neck. The constriction and the special properties of the thermoplastic film material of the bag are the main features of the sealing principle of the invention. A hole that was previously deliberately too small is cut, pierced or punched into the bag wall, in order to then force the flange part through this too narrow opening using auxiliary tools.The film material possesses high stretchability and resilience (rubber band), which means that the film material fits tightly around the neck of the flange. This resilience causes the film material to follow the contours of the constriction. This constriction is the main sealing surface between the bag and the flange. To increase tightness, a deliberately undersized sealing ring is guided over the flange neck. The sealing ring then presses the film material into the constriction. When the lid is closed, it is additionally pressed against the flange collar. This creates an axial sealing component in addition to the radial sealing component of the sealing principle. This doubles the sealing surface and sealing force between the flange and the film wall. Instead of a sealing ring, screwable, multi-part rings made of solid material, hose clamps, hose ties, or safety wires are also conceivable.Additional sealing compounds can be used to further increase the reliability of the seal. Instead of a sealing ring, wrapping with sealing tape is also conceivable.

[0007] An advantageous embodiment of the invention consists in the use of inexpensive bottle necks from PET beverage bottles, or PET blanks (also called "PETLING"). They have the necessary design underlying the sealing principle, with a constriction in the flange neck. PETLINGs can be purchased inexpensively from specialist retailers, including the corresponding lid with a safety lock, and are very lightweight and easy to rework. The lid, which is screwed onto the flange, is located outside and above the bag tank. The extraction of residual air from the bag tank is essential and must always take place at the highest point of the tank. This fact is ideally accommodated by the lid being positioned at the top. A felt element additionally incorporated into the lid further facilitates the extraction of residual air.

[0008] An embodiment of the invention is described with reference to Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8 illustrates. Fig. 1 State-of-the-art tank

[0009] The picture shows a bag tank in a filled state. Hose nipples (6) and (7) are sealed against the bag wall (1) by means of sealing washers (4) and screwed on with threaded nuts (5). One of the hose nipples (6) takes the discharge hose (9) to the consumer outside the tank. The tank pendulum hose (2) is attached to the other side. The tank pendulum (3) is attached to the tank pendulum hose (2). The hose (8) for filling the tank is attached to the hose nipple (7). On the other side of the hose (8) is the ball shut-off valve (10) with a rotating ball shut-off valve (11) and a nipple (12) for attaching a filling hose. The rotating ball shut-off valve (11) is shown closed. Fig. 2 State-of-the-art tank

[0010] The illustration shows a bag tank in a nearly empty state. The bag wall (1) contracts during the withdrawal of the liquid, restricting the space for the tank pendulum (3) and tank pendulum hose (2) connected to the hose nipple (6). This causes the tank pendulum hose (2) to bend and kink. A kink (13) forms on the tank pendulum hose. At the same time, the tank pendulum (3) causes sharp kinks (14) in the bag wall. Fig. 3 State-of-the-art tank with angled hose nipple

[0011] The picture shows a bag tank in a filled state with an angled hose nipple (15). The bag wall (1) seals hose nipples (7) and (15) against the bag wall (1) by means of sealing washers (4) and is screwed together with threaded nuts (5). One of the hose nipples (6) outside the tank holds the discharge hose to the consumer (9). The tank pendulum hose (2) is attached to the other side of the hose nipple (6). The tank pendulum (3) is attached to the tank pendulum hose (2). The hose (8) for filling the tank is attached to the hose nipple (7). On the other side of the hose (8) is the ball shut-off valve (10) with a rotating ball shut-off valve (11) and a nipple (12) for attaching a filling hose. The rotating ball shut-off valve (11) is shown closed. Fig. 4 Embodiment according to the invention

[0012] Shown is a tank whose features meet the protection requirements of a tank fitting for flexible tanks.

[0013] The flange part (16) has a very flat lower part and protrudes only slightly into the bag wall (1).

[0014] The bag wall follows the contours of the flange with its collar (20). A deliberately tight sealing ring (18) encloses the bag wall above the flange base. The sealing ring presses the bag wall against the flange. A cover (17) is screwed onto the top of the flange and accommodates the hose nipples (6) and (21). These are screwed into the cover using threaded nuts (5). The hose nipple (6) screwed into the cover accommodates the hose (2) and the tank pendulum (3). The tank pendulum runs perpendicular to the top of the tank and points towards the center of the tank. The straight hose nipple (21) screwed into the cover is used to fill the tank and extract residual air. It does not protrude into the tank, but is located outside and above the tank chamber. When the flange is closed, the cover presses against the sealing ring (18), which is then pressed downwards against the flange base.The lid may have a safety lock which detaches a retaining ring after the first opening and indicates any unauthorized opening (. Fig. 8) Fig.5 Embodiment according to the invention

[0015] The tank shown is almost completely empty and meets the requirements of a tank fitting for flexible tanks. The individual elements correspond to the specifications described in the previous section. Fig. 4. When the tank is almost completely empty, the hose routing of the tank pendulum hose (2) is kink-free. The tank pendulum (3) can rest gently against both bag walls (1) without causing sharp kinks.

[0016] Fig. 6 Shows a beverage bottle blank / petling (24), with the cap unscrewed (17)

[0017] Fig. 7 shows a flange (16) separated from a petling (24)

[0018] Fig.Figure 8 shows a cover (17) screwed onto a flange (16) with a safety ring (22) and a predetermined breaking point (23). The safety ring engages the collar (20) of the flange (16) when the cover (17) is screwed on. Upon initial opening after screwing, the predetermined breaking point (23) causes the safety ring to detach. This indicates a possible unauthorized opening. List of reference symbols 1 bag wall 2 tank pendulum hose 3 tank pendulum 4 sealing washer 5 threaded nut 6 straight hose nipples 7 hose nipples for filling and emptying / extracting residual air 8 Tank hose for filling and emptying / removing residual air 9 Drain hose to the consumer 10 ball shut-off valve 11 Rotating ball shut-off 12 nipples for attaching the filling hose 13 Hose kink 14 Buckling load 15 angled hose nipples 16 Flange part 17 lids 18 Sealing ring 19 felt element 20 collars 21 Straight hose nipple 22 Safety ring 23 Predetermined breaking point 24 beverage bottle blanks / petlings

Claims

[1] Tank fitting for flexible tanks, consisting of a flange part (16) and a removable cover (17), characterized by that it consists of a flange part (16) which is positively connected to the bag wall. [2] Tank fitting for flexible tanks, according to claim 1, characterized by that the positive fit between the flange part (16) and the bag wall (1) is based on an overstretching of the bag film. [3] Tank fitting for flexible tanks, according to claim 1, characterized by that the positive fit between the flange part (16) and the bag wall (1) is based on the restoring force of the overstretched bag film. [4] Tank fitting for flexible tanks, characterized by that the flange part is provided with one or more collars. [5] Tank fitting for flexible tanks, according to one of the preceding claims, characterized by that a sealing ring (18) below the collar (20) presses the bag wall (1) radially against the flange (16). [6] Tank fitting for flexible tanks, according to one of the preceding claims, characterized by that instead of the sealing ring (18) a sealing tape can also be wound around the flange neck, which presses the bag wall radially against the flange neck. [7] Tank fitting for flexible tanks, according to claim 1, characterized by that the flange part (16) can be manufactured from PET blanks / petlings. [8] Tank fitting for flexible tanks according to claim 7, characterized by that the PET blank is glued to the bag wall. [9] Tank fitting for flexible tanks according to claim 7, characterized by that the PET blank is welded to the bag wall using a heat-sealing process. [10] Tank fitting for flexible tanks, characterized by that the passage of the flange part (16) is large enough to allow hoses, tank pendulums and possible components added later to pass through it. [11] Tank fitting for flexible tanks according to claim 1, characterized by, a flat flange part (16) is incorporated into the bag wall (1), which facilitates the suction of residual air. [12] Tank fitting for flexible tanks, characterized by that the flange (16) can accommodate a felt element (19) which improves the suction of residual air. [13] Tank fitting for flexible tanks according to claim 11, characterized by that a flat flange part, after insertion into the bag wall, facilitates subsequent work. [14] Tank fitting for flexible tanks, characterized by that the base area of ​​the flange (16) is large enough to minimize buckling loads on the bag wall. [15] Tank fitting for flexible tanks, characterized by that a removable lid presses a sealing ring axially against the bag wall (1). [16] Tank fitting for flexible tanks according to one of the preceding claims, characterized by that a removable cover (17) can accommodate more than one hose feedthrough. [17] Tank fitting for flexible tanks according to one of the preceding claims, characterized by that the removable cover is thick enough to allow hose ducts to be screwed in without sealing washers. [18] Tank fitting for flexible tanks according to one of the preceding claims, characterized by that the removable lid allows replacement / maintenance of parts inside the tank. [19] Tank fitting for flexible tanks characterized by that a screwed-on lid incorporates a security ring which separates from the lid after opening and indicates unauthorized opening.

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