EP0000692B1 - Container provided with means for draining off liquid - Google Patents

Description

The invention relates to a container with a device that operates independently of the fluctuating liquid level for the volume-constant removal of liquid from the container.

There are a wide variety of applications in which a constant amount has to be withdrawn from a liquid-filled container over a longer period of time. Often these are so-called buffer tanks, which temporarily store the liquid that arrives in fluctuating amounts over time.

A known device suitable for this purpose contains an exhaust pipe which is attached with its lower end pivotably about a horizontal axis to an outlet pipe socket of the container. The upper end, which has the inlet opening to be held on the liquid surface, is carried by an additional buoyancy body, in particular a float. This float ensures that the inlet opening follows the fluctuating water level exactly.

However, it has been shown in practice that such a buoyancy body is not suitable for ensuring a constant volume removal in all positions of the exhaust pipe. The reason for this is to be found in the fact that the exhaust pipe itself has a considerable lift due to the air space remaining above the liquid flowing through. However, this buoyancy fluctuates depending on the angle of inclination of the discharge pipe, since with increasing steepness the instantaneous water content of the pipe is lower due to the higher flow velocity, and the air content is therefore greater. These influences mean that, with increasing steepness, less and less liquid is drawn off at all, because the leading edge is then above the liquid level.

The object of the innovation is to improve the device of the type described so that the amount of liquid withdrawn over time remains as constant as possible even when the liquid level is very different. This object is achieved according to the innovation in that additional weights and / or additional power means are provided and that lifting or power transmission means are connected to the exhaust pipe, which are arranged and / or guided so that they swing up the exhaust pipe in a buoyancy of the Extraction tube in the opposite direction with the additional weights or forces increasingly in operative connection. These additional weights or force means ensure that the lower edge of the inlet opening is always kept below the liquid level by a constant amount. In general, it is not necessary to provide a steady increase in the forces opposing the lift; it is rather sufficient if this increase takes place in more or less small steps. So you can e.g. Attach a free hanging rope or chain to the exhaust pipe, which carries several smaller additional weights. And the distances of the additional weights to each other and to the attachment point are selected so that when not in use, i.e. with a slight slope of the discharge pipe, lie on the bottom of the container and be lifted from the bottom of the container one after the other from a certain angle. A continuous increase in the counterforce can e.g. can be realized by a tension spring which is connected to the exhaust pipe via a rope or a chain.

• Fig. 1 einen kompletten Behälter mit Abzugsrohr und einer Kompensationsvorrichtung mit Zusatzgewichten;
• Fig. 2 einen Behälter mit einem Zusatzkraftmittel in Form einer Zugfeder;
• Fig. 3 und 4 eine mit der Schwenkachse des Abzugsrohres verbundene Vorrichtung mit Zusatzgewichten.

Some such possibilities are shown in the drawings. Show that:

• 1 shows a complete container with an exhaust pipe and a compensation device with additional weights.
• 2 shows a container with an additional force means in the form of a tension spring;
• 3 and 4 a device connected to the pivot axis of the discharge tube with additional weights.

In Fig. 1, a container 1 is shown, to which liquid is supplied through an inlet pipe, not shown, which can be drawn off through an outlet pipe socket 2 located near the bottom. A slide valve 3 is provided to interrupt the process. The end of the outlet pipe socket projecting into the interior of the container carries a pipe joint 4 for the discharge pipe 5, the upper end of which, which has the inlet opening 6, is held on the liquid surface 8 by floats 7. The float 7 is fastened to the exhaust pipe 5 by means of a joint 9 so that it maintains its position relative to the liquid level.

From the lower part of the drain pipe 5, an arm lo protrudes up over the liquid surface. A rope or chain 11 begins on this arm and, after being deflected around a roller 12, is guided downward outside the container 1 and carries several drivers 13 there one above the other. These drivers are provided for lifting additional weights 14, which in turn rest on supports 15. These supports contain holes of such a size that the carriers can be moved through them. "As can be seen from FIG. 1, the distances between the carriers 13, 13 ', 13" and 13'"in relation to the associated supports 15 , 15 ', 15 "and 15'" dimensioned so that the additional weights 14 are raised one after the other when the rope is pulled up. In the operating state shown, the two are lower weights 14 and 14 'have already been lifted, while the two upper weights 14 "and 14"' are still resting on supports 15 "and 15", respectively. On the basis of the distances between the two upper drivers 13 "and 13"'it can be seen that the next to last but one additional weight 14 "and finally the last weight 14""will be detected when the trigger tube 5 is further erected. If the liquid level in container 1 drops, then the rope also moves down again and deposits the additional weights in reverse order.

A steady increase in the counterforce is achieved with the embodiment according to FIG. 2. There, a piece of rope 11 'is attached to the upstanding arm lo, the other end of which is suspended in the free end of a tension spring 16. A support 17 ensures that the spring 16, the other end of which is suspended in an eyelet 18 fastened to the pool wall, maintains its horizontal position.

In the position lo 'of the arm shown in dash-dotted lines on the left, in which no additional force is yet required, the rope piece 11' loosely sags downward. Only when the position lo has been reached has it tightened so that the spring 16 is increasingly zoned in length as it moves further to the right and thus generates a steadily increasing counterforce.

FIGS. 3 and 4 show a further device working with a gradual increase in the counterforce. Here, a pivot shaft 18 is rigidly connected to the exhaust pipe 5, which is rotatably mounted in two brackets 19, 20. The connection between the exhaust pipe 5 and the shaft 18 is established by a linkage 21. The connection from the discharge pipe 5 to the outlet nozzle 2 is formed by a piece of hose 22.

Driver arms 23, 23 ', 23 "can be clamped on the shaft 18 which rotates when the extraction tube 5 is pivoted. A counterweight 24, 24', 24" is assigned to each driver, each of which has arms with bushes 25 which can be freely rotated on the shaft 18 , 25 ', 25 "are connected. The lower ends of the arms rest against a stop bar 26 as long as the weights 24 are in the rest position.

In the position of the discharge pipe 5 in which the drain opening 6 threatens to be lifted above the liquid level 8, the first driver 23 grips the weight 24 assigned to it and lifts it from the stop 26. Since its lever arm grows steadily with respect to the shaft 18, this also adapts to the likewise increasing buoyancy of the exhaust pipe 5. The next step increase in counterforce occurs when the second or third driver detects the associated counterweight.

Of course, instead of the three counterweights shown, several smaller ones may then be used, so that the approximation to a steady increase in force is even better. The counterweights and their drivers can also be arranged outside the basin, for which purpose the pivot shaft of the exhaust pipe must then be extended accordingly. Such an arrangement would make any adjustment work much easier.

Another quite simple embodiment would be to fasten a rope or a chain near the upper end of the exhaust pipe 5 and to let it hang freely down into the container. Several weights could then be attached to this traction device at intervals, which when not in use, i.e. with the exhaust pipe 5 in a flat position, lie in full on the pool floor and would only be raised in succession beyond a certain angle when the exhaust pipe was raised.

In all the described and illustrated exemplary embodiments, a variety of setting options are provided, so that the trigger device can be optimally adjusted before the first start-up and later adapted to liquids with changing density during operation.

Claims (6)

1. Tank with device for volume constant drainage of liquid out of the tank, functioning independent from a variable liquid level, containing a drainage pipe which is attached to a drainage pipe socket with its lower end pivoting around a horizontal axis. The upper end of the drainage pipe has an inlet opening which has to be kept at the liquid surface, if necessary with aid of an additional mean, i.e. a float which supports the buoyant force of the drainage pipe being partly filled with air, characterized inasmuch that additional weights (14, 24) and/or additional forces (16) are forseen and that lifting resp. force transmissions (11, 23) are connected with the drainage pipe (5). The lifting- resp. force transmissions (11, 23) are arranged and/or guided in such a way that they are functioning more and more together with the additional weights (14, 24) resp. the additional forces (16) i.e. contrary to the buoyant force of the drainage pipe in that moment when drainage pipe lifts upwards.

2. Tank according to claim 1, characterized inasmuch that the means for lifting- resp. force transmissions (11, 11') is a rope, a chain or similar.

3. Tank according to claim 2, characterized inasmuch that the rope or chain which is hanging free to the bottom is fixed to the drainage pipe and that the additional weights are fixed to the rope or chain in their respective distance and in such a distance from the fastening point that they are resting at the tank bottom in case of disuse, i.e. in case of small rise of the drainage pipe. The additional weights should be lifted successively from the tank- bottom when drainage pipe reaches a certain angle of inclination.

4. Tank according to claim 2, characterized inasmuch that the supportings (15) superposed in different height are provided for the additional weights (14) and that the rope resp. the chain is equipped with cams (13) the reciprocal distances of which are smaller than the respective reciprocal distances of the supports (15).

5. Tank according to claim 1, characterized inasmuch that the cams (23) are rigidly connected with the drainage pipe (5) and staggered in such a way that they are able to successively grip and lift the additional weights (24) which are resting on supports or brackets (26) when lifting the drainage pipe (5).

6. Tank according to claim 1, characterized inasmuch that the additional force consists of a spring (16).

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