GAS FLOW CONTROL SYSTEM FOR AN ANALYTICAL INSTRUMENT
First Claim
1. In an instrument for measuring analytically the amount of a gaseous constituent in a gaseous sample mixture by introducing the gaseous sample mixture into a reaction chamber and measuring a characteristic of the gaseous constituent within the reaction chamber, a flow control system for maintaining accurate flow of the gaseous sample mixture into the reaction chamber comprising an upstream flow restricting device and a downstream flow restricting device in series with each other for conducting the gaseous sample mixture to the reaction chamber, bypass flow means connected to the junction of the upstream flow restricting device with the downstream flow restricting device, said bypass flow means including a bypass pump for drawing off a portion of the gaseous sample mixture that has passed through the upstream flow restricting device and regulating means responsive to the pressure difference between the junction of the flow rEstricting devices and the reaction chamber for regulating the pressure at the junction of the flow restricting devices, and an exhaust pump connected to the reaction chamber for drawing gaseous sample mixture from the junction of the flow restricting devices through the downstream flow restricting device and into the reaction chamber.
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Abstract
Gaseous sample mixture flows through two restrictive capillaries in series with each other on its way to a chemiluminescent reaction chamber. A bypass pump has its inlet connected to the junction of the capillaries and its outlet communicating with the atmosphere. A pressure regulator connects the inlet of the bypass pump with the atmosphere. The pressure regulator responds to the pressure difference between the junction of the capillaries and the reaction chamber to control the flow of atmospheric air to the bypass pump inlet and thereby maintains a constant sample mixture flow rate into the reaction chamber despite variations in the pressure of the source of the sample mixture.
21 Citations
4 Claims
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1. In an instrument for measuring analytically the amount of a gaseous constituent in a gaseous sample mixture by introducing the gaseous sample mixture into a reaction chamber and measuring a characteristic of the gaseous constituent within the reaction chamber, a flow control system for maintaining accurate flow of the gaseous sample mixture into the reaction chamber comprising an upstream flow restricting device and a downstream flow restricting device in series with each other for conducting the gaseous sample mixture to the reaction chamber, bypass flow means connected to the junction of the upstream flow restricting device with the downstream flow restricting device, said bypass flow means including a bypass pump for drawing off a portion of the gaseous sample mixture that has passed through the upstream flow restricting device and regulating means responsive to the pressure difference between the junction of the flow rEstricting devices and the reaction chamber for regulating the pressure at the junction of the flow restricting devices, and an exhaust pump connected to the reaction chamber for drawing gaseous sample mixture from the junction of the flow restricting devices through the downstream flow restricting device and into the reaction chamber.
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2. The instrument of claim 1 in which the bypass flow means comprises a flow indicating means located between the junction of the flow restricting devices and the inlet of the bypass pump.
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3. The instrument of claim 1 in which each of the flow restricting devices is a glass capillary tube.
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4. The instrument of claim 1 in which the reaction occurring within the reaction chamber produces chemiluminescence.
Specification
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Current AssigneeAlex D. Colvin
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Original AssigneeAlex D. Colvin
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InventorsColvin, Alex D.
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Primary Examiner(s)Nilson, Robert G.
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Application NumberUS05/194,245Time in Patent Office694 DaysField of Search137/2,3,7,8,9,13,114,117,118 23/254RUS Class Current137/115.09CPC Class CodesG05D 7/03 with auxiliary non-electric...Y10T 137/2594 Choke
