System and Method for Pulsed Canister Sampling
AssigneeEntech Instruments Inc.
InventorDaniel B. CARDIN
Life of this patent
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Abstract
A sampling system for collection of VOCs in air includes a canister and a valve configured to pulse open and closed for the constant introduction of an air sample into the canister over time. Throughout the duration of sampling, the time for which the valve is open for each pulse is modified to compensate for the increasing pressure in the canister, with temperature-compensated pressure readings obtained to ensure a constant mass flow of air into the receiving canister despite pressure changes due to temperature fluctuations during the sampling period.
Claims20
A sampling system, comprising:
- a filtered inlet;
- a first valve coupled to the filtered inlet;
- an outlet configured to fluidly couple to a canister;
- and
- a pressure sensor fluidly coupled to the outlet and configured to measure a pressure inside the canister, wherein the sampling system is configured to perform a method comprising:
- in response to one or more criteria for beginning sampling being met, beginning a sampling process, the sampling process including:
- pulsing the first valve open for variable on times, wherein the variable on times change throughout the sampling process and, during each variable on time, a predetermined fraction of a volume of the canister is filled with sample.
A method comprising:
- at a sampling system including a filtered inlet, a first valve coupled to the filtered inlet, an outlet configured to fluidly couple to a canister, and a pressure sensor fluidly coupled to the outlet and configured to measure a pressure inside the canister:
- in response to one or more criteria for beginning sampling being met, beginning a sampling process, the sampling process including:
- pulsing the first valve open for variable on times, wherein the variable on times change throughout the sampling process and, during each variable on time, a predetermined fraction of a volume of the canister is filled with sample.
A non-transitory computer readable storage medium storing instructions that, when executed by one or more processors in communication with a sampling system including a filtered inlet, a first valve coupled to the filtered inlet, an outlet configured to fluidly couple to a canister, and a pressure sensor fluidly coupled to the outlet and configured to measure a pressure inside the canister, cause the sampling system to perform a method comprising:
- in response to one or more criteria for beginning sampling being met, beginning a sampling process, the sampling process including:
- pulsing the first valve open for variable on times, wherein the variable on times change throughout the sampling process and, during each variable on time, a predetermined fraction of a volume of the canister is filled with sample.
Dependencies are inferred from the claim text.