Mass flow verifiers capable of providing different volumes, and related methods
First Claim
1. A mass flow verifier for verifying flow of a fluid from a mass flow device operating over an operational flow range, the mass flow verifier comprising:
- a system constructed and arranged so as to define different predetermined volumes so as to represent subranges within the operational flow range, each volume comprising an inlet for receiving flow from the mass flow device, and an outlet valve so that pressure changes occurring from flow from the mass flow device into a volume can be measured when the outlet valve is closed;
a temperature sensor constructed and arranged so as to generate a signal representative of the temperature of the fluid within a volume when the pressure changes are being measured within the volume;
a pressure sensor constructed and arranged so as to generate signals representative of the pressure changes in a volume when the pressure changes are being measured within the volume; and
a controller configured and arranged so as to measure flow from the mass flow controller into any select one of the volumes as a function of the manometer pressure signal, the temperature signal, and the size of the select volume.
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Accused Products
Abstract
Embodiments of the present disclosure are directed to systems, methods, and apparatus, including software implementation, useful for high-precision measurement of mass flow rate over a large range of flows by using multiple volumes, each having a different and selected size. Use of a single manometer can facilitate reduced cost, and the use of multiple chamber volumes that are sized according to sub-flow ranges within the overall range of the mass flow verifier, or a related device under test, can provide high accuracy while reducing deleterious effects of noise in the flow measurement.
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Citations
18 Claims
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1. A mass flow verifier for verifying flow of a fluid from a mass flow device operating over an operational flow range, the mass flow verifier comprising:
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a system constructed and arranged so as to define different predetermined volumes so as to represent subranges within the operational flow range, each volume comprising an inlet for receiving flow from the mass flow device, and an outlet valve so that pressure changes occurring from flow from the mass flow device into a volume can be measured when the outlet valve is closed; a temperature sensor constructed and arranged so as to generate a signal representative of the temperature of the fluid within a volume when the pressure changes are being measured within the volume; a pressure sensor constructed and arranged so as to generate signals representative of the pressure changes in a volume when the pressure changes are being measured within the volume; and a controller configured and arranged so as to measure flow from the mass flow controller into any select one of the volumes as a function of the manometer pressure signal, the temperature signal, and the size of the select volume. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of verifying flow of a fluid from a mass flow device operating over an operational flow range, the method comprising:
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defining different predetermined volumes so as to represent subranges within the operational flow range; selectively controlling flow from the mass flow device through an inlet of each volume, and selectively controlling flow from each volume through an outlet valve so that pressure changes occurring from flow from the mass flow device into a volume can be measured when the outlet valve is closed; generating with a temperature sensor a signal representative of the temperature of the fluid within a volume when the pressure changes are being measured within the volume; generating with a pressure sensor a signal representative of the pressure changes in a volume when the pressure changes are being measured within the volume; and measuring flow from the mass flow controller as a function of the manometer pressure signal, the temperature signal, and the known volume of one of the plurality of volumes. - View Dependent Claims (16, 17, 18)
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Specification