Air sampling apparatus

• US 4,040,299 A
• Filed: 11/13/1974
• Issued: 08/09/1977
• Est. Priority Date: 11/13/1974
• Status: Expired due to Term

• Current Assignee: Albemarle Corporation
• Original Assignee: Ethyl Corporation (Newmarket Corporation)
• Inventors: Snyder, Louis J.
• Primary Examiner(s): Yudkoff, Norman
• Assistant Examiner(s): Hollander, Barry I.
• Application Number:
  US05/523,342
• Time in Patent Office: 1,000 Days
• Field of Search: 23/259, 23/292, 23/232 R, 23/254 R, 73/421.5 R, 73/422 R, 73/24
• US Class Current: 73/864.52
• CPC Class Codes: G01N 1/24 Suction devices G01N1/22 - G01N1/2294 take precedence
• CPC Class Codes: G01N 2001/244 using critical flow orifices

Abstract

An apparatus for the continuous collection of a time-weighted gas sample is disclosed. The apparatus inclues a gas reservoir and an openable and closeable gas flow assembly communicating with the reservoir which assembly allows gas to flow at a constant rate from the exterior of the reservoir to the interior of the reservoir when there is a sufficient gas pressure differential between the exterior and interior of the reservoir so that the passing gas achieves a linear velocity in the throat of the gas flow assembly equal to the velocity of sound in the passing gas in the throat. The apparatus of this invention may also include additional gas sample removal assemblies attached to the reservoir.

Claims

1. A personal, portable apparatus worn by an operator for the continuous collection, without operator attention, of a time-weighted gas sample for subsequent analysis which comprises:

a. an enclosed gas reservoir capable of withstanding a pressure differential of about 30 inches mercury;

b. an openable and closeable gas flow means communicating with said gas reservoir for allowing gas to flow from the exterior of said reservoir to the interior of said reservoir at a constant rate when there exists a sufficient gas pressure differential between the exterior and interior of said reservoir so that the passing gas achieves a linear velocity in the throat of said gas flow means equal to the velocity of sound in said passing gas, said reservoir and said gas flow means being sized such that a sample can be obtained over a period up to about 24 hours; and

c. means for attaching the apparatus to the operator.

2. The apparatus of claim 1 wherein said apparatus additionally includes a gas removing means attached to said gas reservoir for removing collected gas in said reservoir for analysis.

3. The apparatus of claim 1 wherein said gas flow means comprises a capillary tube inserted through one wall of said gas reservoir and a valve for opening and closing said capillary to said gas flow.

4. The apparatus of claim 3 wherein the inside diameter of said capillary tube is from about 0.01 mm to about 0.20 mm.

5. The apparatus of claim 2 wherein said gas removing means is a septum mounted in a wall of said reservoir, said septum being penetrable by a hypodermic needle.

6. The apparatus of claim 2 wherein said gas removing means is a valved passage extending through a wall of said reservoir.