755,902. Aerating liquids. BILL, H. and BENNINGER, E. Aug. 12, 1954 [Sept. 15, 1953], No. 23387/54. Class 14(1). Apparatus for impregnating a liquid with gas, e.g. water with CO 2 , has a container 5, Fig. 1, with feed conduits 33 and 24 for the liquid and gas respectively and a discharge conduit 35 for the impregnated liquid, the feed of gas being controlled by a float 10 in the container while the feed of liquid is automatically controlled by the pressure in the container, discharge of the impregnated liquid through conduit 35 being effected by a control device which simultaneously effects discharge of air from the container 5 through air conduit 11 and a valve 12-14. The float 10 is provided on the end of a tube 9 slidable on a fixed spindle 6 through which the conduit 11 passes to terminate in a valve casing 12 containing a spring-pressed valve body 14 controlling an opening 15 to atmosphere, a wire 14a, fixed to the valve body, being connected to a discharge cock (not shown). Pins 8 on the tube 9 co-operate with a central lever 16, one end of which is in contact with a piston 19, Fig. 3, acted upon by a needle 20 having a thickened lower end resting on a valve ball 21 urged upwardly by a spring 22, This ball 21 controls the passage of gas from the conduit 24 through an angular passage 38 leading to a cylindrical boring having a hollow piston 26 containing a pressure spring 27 acting upon an auxiliary piston 28. A further pressure spring 29 tends to maintain the piston 26 in the position shown in Fig. 3 in which it closes an opening 30 leading to an annular conduit 31 formed with openings 32 leading into the container 5. The conduit 31 is connected with the liquid feed conduit 33 which is provided with a lip valve 34. Thus the conduit 31 may be fed with liquid from conduit 33 as also with gas from conduit 24. The upper portion 36 of the discharge conduit 35 receives an arched pipe 37 freely projecting into a recess 40 in base 3 of the container 5. An opening 36a in the pipe portion 36 may be closed by the piston 28 upon actuation of the piston 26, and the opening 37a leading from the pipe 37 to pipe portion 36 is smaller than the opening 36a. On operating a cock on the discharge pipe 35 for discharge of the liquid, the valve body 14 is retracted and the conduit 11 connected to. atmosphere through the opening 15 so that compressed air in the upper portion of the container 5 escapes and the pressure in the container 5 decreases below the liquid pressure within conduit 33 ; liquid therefore enters the container from conduit 33 via the valve 34 and the annular conduit 31. The float 10 is first held down by the force of the spring 22 and then as. more liquid enters the container 5 it moves upwards, and through lever 16, piston 19 and needle 20, the valve ball 21 is forced from its seat against the action of the spring 22 to permit gas to pass from the conduit 24 through passage 38 to displace the piston 26 against the action of the spring 29. The opening 30 is thus freed and gas passes through the conduit 31 into the liquid in the container. Just before the freeing of the opening 30 however, the auxiliary piston 28 closes the opening 36a so that liquid which was first discharged through pipe 35 via the opening 36a now leaves the container via the recess 40, pipe 37, small opening 37a and pipe 35. More liquid thus enters the container than is discharged. As gas enters the container the pressure increases despite the opened conduit 11 until it rises above the pressure of the liquid in the conduit 33 whereupon the valve 34 closes and the feed of liquid is stopped. The float 10 then moves down according to amount of liquid discharged through pipe 35 and the valve ball 21 closes the passage 38 to cut off the supply of gas whereupon the piston 26 is forced back by the spring 29 to close the opening 30. The entrained piston 28 frees the opening 36a so that the liquid may leave the container via this larger opening 36a and the pressure in the container decreases accordingly. As soon as this pressure is below that in the conduit 33, the valve 34 opens for the entry of liquid into the container again, the float is again lifted and the whole operation repeated until the closing of the discharge cock which action at the same time via the wire 14a closes the air conduit 11. A continuous and uniform supply of gas impregnated liquid is thus ensured as long as the discharge cock is open. In a modification, Fig. 4, (not shown) the annular conduit 31 receives gas only and a further annular conduit 41 serves to supply the container with liquid.