Patents by Inventor Clifton D. Crutchfield

Clifton D. Crutchfield has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8528559
    Abstract: Improved respirator fit-test methods and apparatus featuring an automated, respirator wearer-controlled, air-leak measurement system. For fit testing of a respirator positioned on a test subject's face and connected to a controlled negative pressure testing apparatus, the test subject simply holds his breath and then activates a switch in electrical connection with said apparatus, which results in the automatic closure of the breathing port on the respirator and the initiation of a complete fit-testing protocol. The fit-testing apparatus includes a single, self-contained, automated unit that includes a vacuum source, an air-flow measuring device, and an air-pressure transducer for connection to a respirator being tested. By measuring the rate of air exhausted from the respirator in order to maintain a constant challenge pressure, an air leakage rate is determined.
    Type: Grant
    Filed: July 28, 2011
    Date of Patent: September 10, 2013
    Inventor: Clifton D. Crutchfield
  • Publication number: 20110277759
    Abstract: Improved respirator fit-test methods and apparatus featuring an automated, respirator wearer-controlled, air-leak measurement system. For fit testing of a respirator positioned on a test subject's face and connected to a controlled negative pressure testing apparatus, the test subject simply holds his breath and then activates a switch in electrical connection with said apparatus, which results in the automatic closure of the breathing port on the respirator and the initiation of a complete fit-testing protocol. The fit-testing apparatus includes a single, self-contained, automated unit that includes a vacuum source, an air-flow measuring device, and an air-pressure transducer for connection to a respirator being tested. By measuring the rate of air exhausted from the respirator in order to maintain a constant challenge pressure, an air leakage rate is determined.
    Type: Application
    Filed: July 28, 2011
    Publication date: November 17, 2011
    Inventor: Clifton D. Crutchfield
  • Patent number: 8011368
    Abstract: Improved respirator fit-test methods and apparatus featuring an automated, respirator wearer-controlled, air-leak measurement system. For fit testing of a respirator positioned on a test subject's face and connected to a controlled negative pressure testing apparatus, the test subject simply holds his breath and then activates a switch in electrical connection with said apparatus, which results in the automatic closure of the breathing port on the respirator and the initiation of a complete fit-testing protocol. The fit-testing apparatus includes a single, self-contained, automated unit that includes a vacuum source (30), an air-flow measuring device, and an air-pressure transducer (32) for connection to a respirator (10) being tested. By measuring the rate of air exhausted from the respirator in order to maintain a constant challenge pressure, an air leakage rate is determined.
    Type: Grant
    Filed: April 20, 2004
    Date of Patent: September 6, 2011
    Inventor: Clifton D. Crutchfield
  • Patent number: 4765325
    Abstract: Method and apparatus for determining a face respirator fit for a particular respirator on a particular person wherein after first placing the respirator on the person's face, the air interiorly to the facepiece is partially evacuated while the subject holds his breath and clamps off his nostrils, the air which then leaks into the facepiece through leakage paths between the facepiece and the wearer's face is measured by a mass flow meter in line with a vacuum source which maintains a constant negative pressure interiorly to the facepiece, the test being accomplished over a relatively short period of time. The apparatus of the invention includes modifying the respirator by sealing off the normal inspiratory openings, i.e., the inhalation filters, and in their places having ports which connect to the mass flow meter and a pressure monitoring transducer.
    Type: Grant
    Filed: December 12, 1986
    Date of Patent: August 23, 1988
    Inventor: Clifton D. Crutchfield