External volume insensitive flow verification
First Claim
1. A flow verifier for in-situ verification of a device under test (DUT), comprising:
- an inlet connectable to a DUT;
an outlet connectable to a vacuum pump for drawing gas through the DUT and the flow verifier;
a vessel having a predetermined volume;
diffusive media connecting the inlet to the vessel;
an outlet valve connecting the vessel to the outlet for controlling flow from the vessel to the outlet;
at least one temperature sensor operatively connected to the vessel for providing temperature measurements from within the vessel; and
a pressure transducer operatively connected to the vessel for providing pressure measurements from within the vessel.
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Accused Products
Abstract
A flow verifier for in-situ verification of a device under test (DUT), including an inlet connectable to a DUT, an outlet connectable to a vacuum pump for drawing gas through the DUT and the flow verifier, a vessel having a predetermined volume, diffusive media connecting the inlet to the vessel, an outlet valve connecting the vessel to the outlet for controlling flow from the vessel to the outlet, at least one temperature sensor operatively connected to the vessel for providing temperature measurements from within the vessel, and a pressure transducer operatively connected to the vessel for providing pressure measurements from within the vessel.
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Citations
20 Claims
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1. A flow verifier for in-situ verification of a device under test (DUT), comprising:
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an inlet connectable to a DUT;
an outlet connectable to a vacuum pump for drawing gas through the DUT and the flow verifier;
a vessel having a predetermined volume;
diffusive media connecting the inlet to the vessel;
an outlet valve connecting the vessel to the outlet for controlling flow from the vessel to the outlet;
at least one temperature sensor operatively connected to the vessel for providing temperature measurements from within the vessel; and
a pressure transducer operatively connected to the vessel for providing pressure measurements from within the vessel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for in-situ verification of a device under test (DUT), comprising:
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connecting a vessel having a predetermined volume between the DUT and a vacuum pump;
diffusing flow between the vessel and the DUT;
operating the vacuum pump such that gas is drawn through the DUT and the vessel;
providing the DUT with a flow set point and allowing flow and pressure within the vessel to reach a steady state;
stopping flow between the vessel and the vacuum pump;
recording temperature and pressure measurements T, P within the predetermined volume of the vessel at time t=0;
recording temperature and pressure measurements T, P within the predetermined volume of the vessel at predetermined intervals until time t=N;
calculating a time derivative of the vessel pressure divided by the vessel temperature, Δ
(P/T)/Δ
t, based on the temperature and pressure measurements within the predetermined volume of the vessel from t=0 to t=N; and
calculating a flow rate produced by the DUT based upon the time derivatives of temperature and pressure within the predetermined volume of the vessel from t=0 to t=N. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A flow verifier for in-situ verification of a device under test (DUT), comprising:
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an inlet connectable to a DUT;
an outlet connectable to a vacuum pump for drawing gas through the DUT and the flow verifier;
a vessel having a predetermined volume connected to the inlet;
an outlet valve connecting the vessel to the outlet for controlling flow from the vessel to the outlet;
at least one temperature sensor operatively connected to the vessel for providing temperature measurements from within the vessel;
a pressure transducer operatively connected to the vessel for providing pressure measurements from within the vessel; and
a controller connected to the temperature sensor, the pressure transducer and the valve and including a timer, wherein, upon the flow verifier being connected between the DUT and the vacuum pump, the vacuum pump being operated, and the DUT being provided with a flow set point, the controller is programmed to;
open the valve;
allow flow and pressure within the vessel to reach a steady state;
close the valve and record temperature and pressure measurements T, P within the predetermined volume of the vessel at time t=0;
record temperature and pressure measurements T, P within the predetermined volume of the vessel at predetermined intervals until time t=N;
calculate a time derivative of the vessel pressure divided by the vessel temperature, Δ
(P/T)/Δ
t, based on the temperature and pressure measurements within the predetermined volume of the vessel from t=0 to t=N; and
calculate a flow rate produced by the DUT based upon the time derivatives of temperature and pressure within the predetermined volume of the vessel from t=0 to t=N, wherein the flow rate Q is calculated using;
Q=(VvesselTSTP/PSTP)(Δ
(P/T)/Δ
t)where Vvessel is the predetermined volume of the vessel, TSTP is standard temperature of 0°
C. (273.15 K), PSTP is standard pressure of 1 atm (defined as 101.325 kPa), and Δ
(P/T)/Δ
t is a time derivative of the vessel pressure divided by the vessel temperature based on the temperature and pressure measurements within the predetermined volume of the vessel from t=0 to t=N. - View Dependent Claims (20)
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Specification