pressure between the containers i and i 1 equalizes and remaining part of liquid from the pipe portions 6 i and 7 i flow downwardly as a result of the speed produced in the pipe portion 6 i under the action of gravity acceleration the liquid is reflected from the central wall portions of the vessel 2 i flows over the outer wall portions and then outwardly of the vessel 2 i fig4 thus the pipe portion 6 i and the vessel 2 i are released from liquid the container i returns to its initial position when the liquid portion supplied to the lowermost container i 1 is successively passed from the container i to the container i 1 and finally is discharged through the outlet diffuser of the jet pump 9 fig 5 the device returns to its initial position shown in fig1 and a new cycle starts fig6 shows the pipe in accordance with another embodiment in which the pipe has an uninterrupted wall with the above described liquid accumulating containers and pairs of connecting pipe portions the adjacent containers are separated from one another by a single horizontal partition fig7 shows a further embodiment of the invention here the.