Abstract: An analytical instrument suitable for a use in a variety of industrial environments features a housing having a sealed primary chamber filled with a dry, inert gas at a first static pressure. An instrumentation system is disposed within the primary chamber, where fire hazard is eliminated by the inert gas. The housing additionally includes a reference chamber holding a gas a second pressure lower than the first pressure. One or more pressure switches, in pressure-sensing relationship with both chambers, is operative to interrupt the application of power to the instrumentation system if the differential between first and second pressures falls below a predetermined value. In this manner, the instrumentation system is rendered safe whenever the primary chamber is breached or otherwise loses inert gas pressure.

Abstract: A Raman spectrometer optically separates an optical signal scattered by a sample from an incident excitation light beam into an unshifted return component at a first wavelength and one or more Raman scattered components at shifted wavelengths characteristic of the sample. The unshifted return component—but not the Raman scattered components—is attenuated prior to impinging on an optical detector. The unshifted return then serves as the basis for real-time calibration to account for fluctuations in optical intensity, wavelength shift, and/or spectral peak width, based on a comparison of the unshifted return peak to a reference standard for stable reflectance.

Abstract: A rule-based verification testing methodology automates the process and allows for field deployment of verification testing instrumentation. A rule-based chemical monitoring methodology automates the verification of a chemical being monitored, as well as the instrument and a sample path, increasing the confidence in the verification process. In both methods, at least Raman spectra of a sample are captured, and compared to a model that is based on reference data. Predetermined, flexible, parameterized rules control the comparison. Additional physical properties, such as color and size, may also be compared (also controlled by predetermined rules).