Method and apparatus for sensing the flux of a flowing fluid

Claim 1

Apparatus for determining the flux of a fluid having a particle density N comprising: means for providing a region having an axis along which the fluid flows in passing therethrough, the region having a cross sectional area A which is perpendicular to the axis; charged particle source means capable of maintaining an electric potential V and extending essentially perpendicular to the flow axis to provide charged particles in the fluid adjacent to the source means; first collection means separated from the charged particle source means by a distance L 1 and extending across the region essentially perpendicular to the flow axis to collect charged particles which drift from the charged particle source means along the flow axis in the direction of flow of the fluid and form a first electric current, I 1 , said first means being capable of either a positive or negative electric potential with respect to the charged particle source means; second collection means separated from the charged particle source means by a distance L 2 and extending across the region essentially perpendicular to the flow axis to collect charged particles which drift from the charged particle source means along the flow axis in the direction opposite to the flow of the fluid and form a second electric current, I 2 , said second collection means being capable of an electrical potential which is of the same sign as the potential of the first collection means; means for providing an electric field E, essentially coaxial with the direction of fluid flow between the charged particle source means and both the first and second collection means to induce charged particles to drift parallel to the axis toward the first and second collection means, the strength of the field E and the pressure of the fluid P allowing the operating range in the ratio E/P to cause the ion mobility at standard conditions of temperature and pressure to remain constant between the first and second collection means; means for sensing the first electric current I 1 ; means for sensing the second electric current I 2 ; and means for sensing the potential difference between the charged particle source means and the first and second collection means to allow a combining of I 1 , I 2 and V with the apparatus parameters A, L 1 and L 2 , and the number density of particles at standard conditions N o , with the standard ion mobility of the fluid, to directly relate the fluid flux passing through the area A to the ratio of the difference in the electric currents, (I 1 -I 2 ) to the sum of the electric currents, (I 1 +I 2 ).

Claim 16

The method of measuring the mass flow of a fluid including the steps of: flowing the fluid along an axis; creating a region of charged particles in the fluid substantially transverse to the axis wherein the region through which the fluid passes has a cross sectional area A; applying a substantially uniform electric field along the flow axis between the region of charged particles and both an upstream charged particle collector and a downstream charged particle collector; maintaining the electric field (E) to fluid pressure P ratio, E/P such that the ion mobility at standard conditions of temperature and pressure remain constant in the region between the upstream and downstream charged particle collector; sensing the electric current flow due to the movement of charged particles from the region of charged particles to the upstream and downstream collectors respectively; sensing the potential difference V between the charged particle source region and the upstream and downstream charged particle collectors; determining the distances L 1 and L 2 between the upstream and downstream collectors and the charged particle source region; determining the ratio of the difference and the sum of the upstream and downstream currents, multiplying this ratio by the reduced ion mobility μ o , the gas density at standard conditions N o , the applied potential V, and the cross sectional area of fluid flow region A, and dividing this product by the appropriately weighted ratio of drift field lengths L 1 and L 2 ; and multiplying the resulting value by the average mass of the fluid particles.

Claim 17

The method of measuring the mass flow of a fluid including the steps of: flowing the fluid along an axis; creating a region of charged particles in the fluid substantially transverse to the axis wherein the region through which the fluid passes has a cross sectional area A; applying a substantially uniform electric field along the flow axis between the region of charged particles and both an upstream charged particle collector and a downstream charged particle collector; maintaining the electric field (E) to fluid pressure P ratio, E/P such that the ion mobility at standard conditions of temperature and pressure remain constant in the region between the upstream and downstream charged particle collector; sensing the electric current flow due to the movement of charged particles from the region of charged particles to the upstream and downstream collectors respectively; sensing the potential difference V between the charged particle source region and the upstream and downstream charged particle collectors; determining the distances L 1 and L 2 between the upstream and downstream collectors and the charged particle source region; determining the ratio of the difference and the sum of the upstream and downstream currents, multiplying this ratio by the reduced ion mobility μ o , the gas density at standard conditions N o , the applied potential V, and the cross sectional area of fluid flow region A, and dividing this product by the appropriately weighted ratio of drift field lengths L 1 and L 2 ; and multiplying the resulting value by the average mass of the fluid particles.