The invention relates to a liquid siphon for emptying containers, especially drums, filled with liquid, with a suction pipe which can be inserted in the container wherein the upper end section of the siphon includes a connecting piece for connection to a pump.
Liquid siphons of the above-identified type generally have a VA suction pipe, which is lowered through the container opening into the container to the bottom of the container. The upper end of the suction pipe includes a connecting piece, for example, a threaded coupling, with which the suction pipe can be connected to a pump. The nominal diameter of the suction pipe is selected as large as possible, so that the liquid can be siphoned off from the container in a relatively short time. But the large pipe cross section has the drawback that the container can be emptied only to a residual amount of 1-2 liters. The reason for this lies in the fact that the pumps used must not siphon any air. The pump has to be turned off immediately as soon as air is sucked in with the liquid. These pumps generally have a monitor which turns off the pump at the right time. The amount of liquid contained in the suction pipe then runs back into the container. Another drawback of the known liquid siphons is that the residual amounts on the bottom of the container are frequently not picked up at all. The remainder of the container content, e.g., the solvent, remains in the container and is therefor never used.
Since shipping drums or shipping containers have to be cleaned, this residual amount is mixed with the washing water which must be disposed of at high expense to avoid damage to the environment by distillation or distillate combustion.