Powerless air charging apparatus, system, and method

A liquid storage system having a minimum operating pressure, comprising:

• a liquid storage tank;
• a venturi coupled to said liquid storage tank and configured to siphon gas from a gas supply in response to a liquid flow through said venturi;
• a charging tank coupled to said venturi and configured to receive a liquid-gas flow from said venturi, wherein gas from the liquid-gas flow is retained in the charging tank;
• and
• a liquid supply coupled to said charging tank, wherein the liquid is supplied from said liquid supply through said charging tank to said liquid storage tank, and wherein the gas retained in the charging tank is forced into the liquid storage tank to maintain at least a minimum operating pressure;
• wherein in response to the liquid supply being active, there is substantially no liquid flow through the venturi, and
• wherein in response to the liquid supply being inactive, liquid from said liquid storage tank is supplied to said venturi, such that said gas is siphoned from said gas supply and introduced to and mixed with said liquid to create the liquid-gas flow.

A method for supplying gas to a liquid storage tank to maintain an operating pressure in said liquid storage tank, comprising:

• providing a charging tank coupled to a liquid supply;
• providing a storage tank coupled to a charging tank outlet;
• providing a venturi coupled to a storage tank outlet and an inlet of said charging tank, wherein said venturi comprises a vent coupled to a gas source;
• supplying a liquid flow from said storage tank to said inlet venturi;
• siphoning a gas from said gas source in response to said liquid flow;
• and
• discharging a liquid-gas flow from said venturi;
• wherein in response to the liquid supply being inactive, liquid from the storage tank supplies said liquid flow to the venturi, such that said gas is siphoned to create said liquid-gas flow which is discharged to said charging tank.