Abstract: A micromachined mass spectrometer includes an ionizer, a separation region and a detector. The ionizer is formed from an upper electrode, a center electrode and a lower electrode. Ionization of a sample gas takes place around an edge of the center electrode. Accelerating electrodes extract ionized particles from the ionizer. Ionized particles are accelerated through the separation region. A magnetic field is applied in a direction perpendicular to travel of the ionized particles through the separation region causing the trajectory of the ionized particles to bend. The mass spectrometer is formed using micromachined techniques and is carried on a single substrate.

Abstract: The photometer of the present invention includes an optical system in which an emission beam generated by pulsed ultra violet radiation from a source is split into a sample beam and a reference interference beam by spectrally selective mirrors arranged in series. These mirrors reflect a beam having a wavelength range corresponding to an absorption wavelength of the gas to be detected onto one solid state detector and to pass a beam to a second spectrally selective mirror where a beam having second range of wave lengths corresponding to an interfering gas is reflected onto a second solid state detector. This second beam serves to measure the interfering gas and also as an imperfect reference channel. In a preferred embodiment the radiation from the source is split prior to entering the sample cell.

Abstract: A method and apparatus are disclosed for measuring a resistance of a sensor. The apparatus injects a first test current into the sensor and then measures a substantially stable first voltage level across the sensor when the first test current is present. The apparatus then injects a second test current into the sensor, the second test current being substantially equal to but opposite in polarity to the first test current. A substantially stable second voltage level across the sensor is measured when the second test signal is present. Using the first measured voltage level and the second measured voltage level, the apparatus calculates the resistance of the sensor.

Abstract: A micromachined mass spectrometer includes an ionizer, a separation region and a detector. The ionizer is formed from an upper electrode, a center electrode and a lower electrode. Ionization of a sample gas takes place around an edge of the center electrode. Accelerating electrodes extract ionized particles from the ionizer. Ionized particles are accelerated through the separation region. A magnetic field is applied in a direction perpendicular to travel of the ionized particles through the separation region causing the trajectory of the ionized particles to bend. The mass spectrometer is formed using micromachined techniques and is carried on a single substrate.

Abstract: An analyzer measures properties of multiple chemical samples, and includes an optical filter element having a long axis and positioned at a location where simultaneous multiple light beams, corresponding to the chemical samples to be measured, form a diffuse light spot elongated along an axis which is substantially aligned with the filter element long axis. The analyzer also includes a light source, filter means incorporating the filter element for transmitting spectrally selected portions of the light beams, sample cell means for exposing each sample to its associated light beam, and detector means for detecting the light beams after modification by the samples and after transmission by the filter. In a preferred embodiment, optical fibers carry the light beams to and from the chemical samples.

Abstract: An apparatus and method for measuring potentiometric electrode impedance for diagnostic purpose while continuously reading the results of the process value. A square wave is applied to an external circuit, which in turn is coupled to an electrode assembly output through a capacitor. The output of the electrode is converted into a pulse width modulated signal and sampled. These sampled values are used to calculate the impedance and process output value.

Abstract: A combustible gas sensor includes a housing defining an interior containing a reference bead and a measurement bead which are fully exposed by the removal of the shroud or can therefrom. The beads are electrically connected in series and the reference bead is connected in parallel with a resister to define one side of a Wheatstone bridge. A liner consisting of a disk defining an inner face and an outer face overlies the reference and measurement beads. The inner face of the disk is provided with a slot opening at the inner face which is dimensioned to receive the reference and measurement beads therein. The slot provides a confined space for fluid communication between the fully exposed beads. A through running opening is disposed in the disk on each side of the slot adjacent the end of the slot in which the reference bead is disposed. A channel extends from each of the openings and communicates with the slot.

Abstract: A retraction mechanism permits easily removing a sensor assembly from a pressurized process fluid container through a valve attached to an opening in the container. The retraction mechanism includes a folding support linkage having a first end and a second end formed from at least two links that are joined together to have a pivot joint located therebetween. The first end of the support linkage is joined to the sensor assembly, while the second end of the support linkage is joined to the valve or the fluid container. The two links are partially folded when the sensor assembly is in operable position, and pivot about the pivot joint to unfold when the sensor assembly is removed. The retraction mechanism further includes a damper connected between the two links of the support linkage. The damper provides a damping or restraining force for the sensor assembly as the sensor assembly is removed from the fluid container.

Abstract: A remote gas measuring apparatus and method utilizes the optical absorption line characteristics to determine an amount of gas of interest as may exist in an area under study. The remote gas measuring apparatus includes a source of electromagnetic radiation that can be projected toward the area in question and a light collecting arrangement. The light signal received is coupled to a fast light switch modulator which modulates the light signal to a first frequency. A second modulating arrangement modulates the light signal to a second frequency and includes a birefringent etalon device having a periodic spacing equal to the periodicity of the absorption lines of the gas of interest. The second modulating means is further effective such that, when an electric field is applied thereto the transmission spectra associated with the light signal is shifted between spectra which coincide with the absorption lines and spectra which fall between the absorption lines.