Aspirator pump and metering device
AssigneeAluminum Company of America
InventorCharles E. Eckert
Life of this patent
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Abstract
An apparatus is disclosed for controlling flow rates of a primary fluid including aspirating, mixing, and metering the primary fluid with a secondary fluid. In one aspect, the invention includes means for passing a secondary fluid of diluent gas through a venturi having specified proportions including discharge coefficient; and means for pumping primary fluid through venturi suction to pass through a primary fluid orifice of specified discharge coefficient wherein the venturi discharge coefficients of the venturi and the liquid orifice form a substantially linear proportionality over a wide range of flow rates through the venturi.
Claims18
Fluid flow control apparatus comprising:
- an aspirator including a liquid orifice and a venturi for pumping at a low flow rate such that the Reynolds number is less than 30,000 and mixing a liquid into a diluent gas to form a vapor mixture having a substantially constant volume fraction independent of flow rates;
- and
- means for metering the flow rate of said vapor mixture;
- wherein said aspirator comprises said venturi and said liquid orifice having a configuration such that its venturi discharge coefficient C.sub.DV and its liquid orifice discharge coefficient C.sub.D2 forms a ratio C.sub.DV /C.sub.D2 substantially linear over flow rates below the said Reynolds number of 30,000 above which the discharge coefficients become invariant.
A fluid control device for controlling flow of a corrosive, volatile liquid comprising:
- a flow casing;
- a venturi insert within said flow casing, said insert selected to have specified proportions including a discharge coefficient;
- a liquid orifice of specified discharge, coefficient;
- and
- means for passing at a low rate of flow such that the Reynolds number is less than 30,000 said liquid by venturi suction through said liquid orifice of specified discharge coefficient and into the venturi at a position at or near the vena contracta of said venturi;
- wherein,
- C.sub.VD =the discharge coefficient for the venturi;
- C.sub.D2 =the discharge coefficient for the liquid orifice;
- and
- C.sub.DV /C.sub.D2 forms a substantially linear proportionality over flow rates below the said Reynolds number of 30,000 above which the discharge coefficients become invariant.
In an aspirator for pumping a primary fluid employing the momentum of a secondary fluid, the improvement for measuring flow rates of said primary fluid by controllably mixing said primary and secondary fluids and metering the mixture to form a metered mixture of predetermined composition independent of flow rates, comprising:
- a venturi;
- means for passing said secondary fluid through said venturi having a discharge coefficient C.sub.DV ;
- a primary fluid orifice;
- means for pumping said primary fluid at a low flow rate such that the Reynolds number is less than 30,000 through suction by said venturi to pass through said primary fluid orifice having discharge coefficient C.sub.D2 ;
- wherein,
- C.sub.DV =the discharge coefficient for the venturi;
- C.sub.D2 =the discharge coefficient for the primary fluid orifice;
- and
- C.sub.DV /C.sub.D2 forms a substantially linear proportionality over flow rates below the said Reynolds number of 30,000 above which the discharge coefficients become invariant;
- and
- means for mixing and measuring said primary and secondary fluids.
Dependencies are inferred from the claim text.