Apparatus for consecutively dispensing an equal volume of liquid

Apparatus for consecutively dispensing an equal volume of a liquid from a storage tank, said apparatus comprising:

• a hermetically sealed metering chamber at least partially submerged beneath the standing level of liquid in said tank, said metering chamber having an inlet port communicating with the interior of said tank beneath said level;
• one-way valve means for accommodating an inflow liquid into said metering chamber from said tank via said inlet port, and for blocking an outflow of liquid from said chamber via said inlet port into said tank;
• a plurality of discharge conduits communicating with the interior of said metering chamber, said discharge conduits having varying penetration depths beneath the level of liquid contained in said metering chamber;
• valve means for selectively opening any one of said discharge conduits and for closing the other of said discharge conduits;
• means for pneumatically elevating the pressure in said metering chamber to thereby discharge liquid contained therein via said open discharge conduit, the volume of the thus discharged liquid being a function of the penetration depth of said open discharge conduit;
• and
• vent means for relieving said pressure to thereby replenish the thus discharged liquid with an inflow of liquid from said tank via said inlet port.