Patent Application
20180274729
The invention relates to an overfill protection means in a tank container according to the preamble of claim 1. Such an overfill protection means is known from the publication GB 2 329 007 A.
Overfill protection means are required especially for safe storage of liquefied gases or other liquids in tank containers in order to limit the height of the liquid level and thereby the maximum mass within the tank during the filling of the tank container, whereby safe storage can be ensured permanently irrespective of environmental influences (temperature, solar radiation, etc.).
In this connection, overfill protection means are generally known which comprise a float which is directly connected to a closure via a connecting element. By filling the tank container, the float is moved upwards with the steadily rising liquid level, whereby the closure coupled to the float is moved into a position closing the fill opening. Upon reaching a predetermined fill level, the fill opening is completely closed by the closure, whereby further filling is prevented and the filling process is thus stopped. Such an overfill protection means is known, for example, from the patent US 2010/0288774 A1.
Furthermore, overfill protection means are known which are formed by a tubular housing and comprise a cylindrical float, wherein the diameter of the float is smaller than the diameter of the tubular housing. As a result, the overfill protection means can be mounted from the outside in any tank container with an appropriate receptacle, e.g., a flange. Such an overfill protection means is known, for example, from the patent FR 2 476 790. The tubular housing of the overfill protection means disclosed in the patent FR 2 476 790 has a fill opening which is closable by means of a closure movably mounted in the housing, which is triggered by the float depending on the liquid level prevailing in the tank container. The closure and the housing form a cavity, wherein part of the liquid flowing into the tank container is continuously branched off and guided into the cavity. The cavity has a drain through which the level accumulating in the cavity can run off. Upon reaching a certain preset liquid level, the float closes the drain of the cavity, whereby the cavity fills up steadily and, upon exceeding its maximum fill level, pushes the closure movably mounted in the housing against the tank fill opening, thus stopping the filling process. A further overfill protection means of this type is known from the U.S. Pat. No. 4,313,459. The filling protection means disclosed in the U.S. Pat. No. 4,313,459 is composed of a standard operating valve to which an overfill protection unit is attached by means of a thread. The standard operating valve thereby serves as a connection for the filling hose, wherein, by means of a hand wheel attached thereto, the filling process can be terminated also manually directly on the valve. The overfill protection unit is composed essentially of a cylinder having a blind hole, which blind hole is directly adjacent to the standard operating valve and communicates with the interior of the tank container via lower and upper openings fitted in the lateral surface of the cylinder. Upon reaching a certain preset liquid level, a sleeve is slid over a cylinder by the float, whereby a cavity is created between the sleeve and the cylinder. If the sleeve covers the lower openings, part of the liquid floods the cavity, whereby, as result of the filling pressure of the liquid, the sleeve will slide over the residual lateral surface of the cylinder, covering also the upper openings of the sleeve, without any further contribution from the float. As a result, all openings through which the liquid might flow into the tank are covered by the sleeve, and the filling process is stopped. If the standard operating valve is closed, the pressure in the cavity decreases, and a pre-loaded spring pushes the float back down.
The embodiments known from the prior art turn out to be disadvantageous in that the overfill protection means in most cases show only a gradual closing sequence, whereby, using overfill protection means of that kind, a clear signal that the overfill protection valve is closed usually cannot be obtained. In addition, the gradual closing process leads to longer filling times during the filling of a tank container, in particular for tank containers which have a large horizontal, but small vertical extension. Furthermore, such known overfill protection means are susceptible to failure, since cylindrical floats are more prone to getting stuck and jamming, respectively. As a result, the risk arises that the float will not activate reliably or not at all and that, subsequently, increased evaporation losses will occur.
The invention is based on the object of building an overfill protection means which, due to its simple structure, will last for the whole service life of a tank container and, upon reaching the maximum tank fill, will close the filling line abruptly, thus reliably preventing the tank container from being overfilled.
According to the invention, this problem is solved by an overfill protection means having the features of claim 1 and of claim 10. The dependent claims relate to further particularly advantageous embodiments of the invention.
The overfill protection means according to the invention comprises at least one actuating element, and the trigger mechanism is formed by at least one locking element, with the float acting upon the at least one locking element via the at least one actuating element. A guide is designed on the outer lateral surface of the housing. The at least one actuating element can be formed by a tube piece which is put over the housing, is guided by the guide and acts upon the at least one locking element with a changing contour of its inner lateral surface. The actuating element can also be formed by at least one lever which acts upon the at least one locking element in a gravity-loaded or spring-loaded manner, wherein the float is displaceable relative to the lever.
By means of the overfill protection means according to the invention, it is possible to abruptly and reliably stop a filling of a tank container for storing liquefied gases. Because of the rising liquid level with the filling of the tank container, a trigger mechanism is activated by the float as soon as a preset maximum filling volume of the tank container is reached. In doing so, a closure located in the filling path, towards which the liquefied gas is flowing, is released by the trigger mechanism, whereby the closure is flung abruptly into a closing position shutting off the filling path via the pressure of the flowing fluid. In this regard, the filling path defines the path taken by the fluid as it flows from the filling line through the overfill protection means into the tank container. The abrupt stopping of the filling has the advantage that a point in time at which the overfill protection means or, respectively, the trigger mechanism is activated can be detected accurately, for example, by a sensor or an appropriate signal detection means. This can be accomplished, for example, by a pressure sensor in the filling line. Furthermore, an advantage obtained by the design according to the invention of the overfill protection means is that, as result of the abrupt stopping of the filling, the full flow cross-section will be preserved until the end of the filling process, whereby there will be no unnecessary prolongation of the filling-up process.
Furthermore, by the structural design according to the invention of the overfill protection means, the advantage is obtained that, even in case of vibrations, strong accelerations or light blows, for example, due to liquid building up in a truck tank as a result of braking or acceleration processes, damage to the overfill protection means is prevented and, at a standstill of the vehicle, said means will immediately be fully operational again.
In this context, the housing has, particularly advantageously, a tubular design and is manufactured from stainless steel. By using stainless steel, the housing can be assembled easily with other parts of the tank container, as they are generally made of stainless steel in the preferred fields of application such as, for example, in the storage of liquefied gases or also in the food industry.
Preferably, the closure is designed in the form of a valve and has a counterseat surface, wherein the tubular housing has a valve seat incorporated into the housing. In this way, the advantage is obtained that, when the closure is in the closing position, the valve seat and the counterseat surface sealingly abut against each other because of a pressure prevailing in the filling line, and, thus, a particularly good sealing can be achieved. In this context, the closure is advantageously made of brass, whereby a particularly good safeguarding against leakage of the valve is achieved. Not only does brass have very good sealing properties, brass also has very good processing characteristics and particularly good sliding properties. Because of that, the closure can be mounted displaceably in a guide fitted directly in the housing without any lubrication being provided. A further advantage of constructing the housing from stainless steel and of constructing the closure from brass proves to be that brass and stainless steel are not prone to cold welding. So as to further increase the sealing effect between the housing and the closure, the possibility exists to use other materials such as, e.g., rubber rings as elements constituting sealing surfaces. For example, a valve seat ring made of rubber may be fitted into the housing.
In a particularly inexpensive embodiment variant, the trigger mechanism is formed by several engagement levers which, rotatably mounted to the housing, engage the closure by means of, in each case, one engagement knob formed on them and keep said closure in the open position releasing the filling path or, respectively, release the closure, which is triggered by the float, when the maximum filling capacity of the tank container is reached. Advantageously, the design of the engagement levers is as light-weight and stiff as possible. For this reason, the engagement levers are preferably made of aluminium.
The float is coupled to the trigger mechanism via at least one actuating element. The trigger mechanism can be formed by locking elements in the form of balls or pins, and the closure may have at least one indentation, for example, a rounded groove, into which the locking elements engage when the closure is in the closing position. In this way, a very low-friction coupling between the closure, the trigger mechanism, the actuating element and the float can be achieved. According to the invention, the at least one actuating element is formed by a tube piece or by several levers. In a further embodiment variant, the at least one actuating element is formed by several levers or rods which engage each other, whereby the float can be arranged irrespective of the position of the housing in the tank container. This indeed increases the production-related expenditure, but decreases the mechanical strain on the components, especially on the trigger mechanism, in case of vibrations or strong accelerations.
In one variant of the invention, the overfill protection means suitably comprises a compression-proof and closed float. In this embodiment, the compression-proof, closed float may be exposed also to high overpressure or, respectively, rapidly changing pressures, without the float undergoing a deformation. Advantageously, a tank filling valve according to the invention comprises a torus-shaped float. A torus-shaped float provides the advantage of little dependency on the density of the stored liquid, since said float shape has a flat structure with a large surface area in relation to its construction height. Thus, a substantially proportional displacement of the torus-shaped float depending on the fill level of the stored liquid is ensured. Depending on the intended use and the liquid, floats can be used which have one cavity or several cavities. Thus, for example, the use of sponges or porous materials is conceivable as well.
In a further alternative variant of the invention, the float in a tank filling valve is open at least in sections. For example, such a float has sections which are open downwardly or, respectively, on an underside of the float.
In a preferred embodiment variant, the float is mounted so as to be displaceable in an axial direction, whereby unintended pinning or blocking of the float can be avoided and, hence, an operation of the overfill protection means of the tank filling valve can be ensured which is as failure-free as possible. In a torus-shaped float, said float is arranged, for example, coaxially to the tubular housing and is guided along the housing via the actuating element or other appropriate elements such as, for example, different types of guides. Particularly suitably, a lower and an upper stopper are formed at the tubular housing in a tank filling valve according to the invention, whereby the displacement of the float relative to the housing is restricted. The lower stopper is advantageously designed on the tubular housing and constitutes the stopper on which the at least one actuating element and/or the float rest(s) when the trigger mechanism is in the engaged position. Advantageously, the tubular housing is arranged in the installation position with its longitudinal axis vertical in the tank container, whereby the at least one actuating element and/or the float rest(s) on the lower stopper due to gravity. If the overfill protection means and hence the tubular housing are arranged in an arbitrary position within the tank container, the trigger mechanism or, respectively, the float is advantageously kept in the engaged position at the lower stopper by means of a spring force which is lower than the buoyancy force of the float. The upper stopper is the stopper on which the at least one actuating element and/or the float abut(s) when the trigger mechanism is in the release position.
Particularly advantageously, in a tank filling valve according to the invention, the float and the trigger mechanism coupled to it or, respectively, the actuating element coupled to it adjust the liquid level in the interior of the tank container at which the locking mechanism releases the closure. In the following, the liquid level at which the maximum filling capacity of the tank is reached, is referred to as the trigger level.
Further advantageous embodiments of the overfill protection means according to the invention are illustrated in further detail by way of example hereinbelow with reference to the figures.
In the embodiment variant illustrated in
According to a further embodiment variant, the closure 113 is moved into the open position releasing the filling path 126 due to a spring force, after the liquid supply to the overfill protection means 101 has been interrupted.
According to a further embodiment variant, the tube piece 120 rests on the lower stopper 123 by means of a spring force, at a liquid level below the trigger level.
According to a further embodiment variant, a relief bore 128 is formed in the valve plate 114, the relief bore being connected to the blind hole 116. In order to prevent leakage currents and to ensure abrupt closing, the diameter of the relief bore 128 is advantageously very small. The relief bore 128 prevents liquefied gas from being trapped between the closure 113 located in the closing position and the tank coupling, which is not illustrated, if the filling line is closed. Instead of the relief bore 128, an overpressure valve might be provided.
If the liquid level is below the trigger level, the torus-shaped float 124 rests on the levers 320 due to gravity, whereas the torus-shaped float 124 keeps the balls 112 in the engaged position due to the geometry of the levers 320, whereby the closure 113 is kept in the open position releasing the filling path 126. Depending on the intended use of the overfill protection means 301, different numbers of balls 112 and levers 320 may be used, wherein, as illustrated in
According to a further embodiment variant, the closure 113 has a shorter valve stem 115, whereby the closure 113 is kept in the open position by means of the upper edge 130, while being supported on the balls 112. The balls 112 are thereby protected against falling into the tubular housing 103 by recesses 111 which converge slightly toward the inside in a conical fashion.
If the liquid level is below the trigger level, the float 124 rests on the lower stoppers 423 due to gravity. In this embodiment variant, the lower stopper 423 is configured as a ring which is firmly connected to the housing 103. The weight of the levers 420 pushes the balls 112 into the rounded groove 118 of the closure 113 according to the lever principle, thus keeping the latter in the open position releasing the filling path 126. Upon reaching the trigger level, the float 124 lifts the levers 420, whereby, in turn, the closure 113 is released by the balls 112 and flings into the closing position. By means of an upper stopper, which is not illustrated, the path of the float 124 can be given an upper limit, and/or the balls 112 can be prevented from falling out of the tubular housing 103. If the liquid supply to the overfill protection means 401 is interrupted, the filling pressure decreases and the closure 113 falls due to gravity on a side surface 127 of the spacer 107 and into the open position releasing the filling path 126. If, as a result of the removal of a sufficient amount of liquefied gas, the liquid level has fallen again to such an extent that the float 124 no longer presses against the levers 420, the weight of the levers 420 pushes the balls 112 back into the rounded groove 118 of the closure 113 located in the open position, whereby said closure is held.
According to a further embodiment variant, the lower stopper 423 is formed by several rods distributed at equal intervals around the tubular housing 103, wherein one rod at a time is connected to one lever 420, respectively. As a result, the advantage is obtained that the weight acting upon the balls 112 for keeping the closure 113 in the open position according to the lever principle is increased, since the weights of the lower stopper 423 and the float 124 are added to the weight of the levers 420. This embodiment variant is suitable especially for inflowing liquid streams of high density in large amounts.
Upon reaching the trigger level and thus the maximum capacity, the float 124 moves the catch elements 131 into the filling path (shown in the right half of the image of
According to a further embodiment variant, the catch elements 131 are displaced by means of a spring force back into a position adjacent to the float 124, if the filling path 126 is interrupted, and further into a position outside of the filling path 126, if the float 124 sinks down.
According to a further embodiment variant, the tube piece 520 is displaced by means of a spring force into a position in which the tube piece 520 rests on the lower stopper 523, if the closure is in the open position releasing the filling path 126.
The embodiment variants illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| A 51084/2015 | Dec 2015 | AT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AT2016/060129 | 12/15/2016 | WO | 00 |
