Abstract: A pressure transmitter apparatus having a unitary body portion, separate diaphragms and flange elements and disposed within the body, a first and second normally vertical pressure passage. The first and second pressure passageways communicate respectively between first and second pressure openings extending normally horizontally through the body portion, and a transducer mounting element. The mounting element, coupled to the body portion and located above the pressure passageways, mounts a transducer that generates a differential pressure signal. One or a pair of diaphragm elements are configured to form first and second process diaphragms, closing first and second pressure openings. The flange element overlies the diaphragm element and is removably and replaceably secured to the body portion.

Abstract: A pressure transmitter apparatus having a unitary body portion, separate diaphragms and flange elements and disposed within the body, a first and second normally vertical pressure passage. The first and second pressure passageways communicate respectively between first and second pressure openings extending normally horizontally through the body portion, and a transducer mounting element. The mounting element, coupled to the body portion and located above the pressure passageways, mounts a transducer that generates a differential pressure signal. One or a pair of diaphragm elements are configured to form first and second process diaphragms, closing first and second pressure openings. The flange element overlies the diaphragm element and is removably and replaceably secured to the body portion.

Abstract: A selectively pressured housing apparatus comprising a body, a wall member, an aperture, and a mounting seat. The body has a chamber therein extending along a first axis, is open at a first axial end and a second axial end, and has a port extending along a second axis transverse to the first axis. The port communicates with the chamber. The wall member is inside of the body and extends transverse to the first axis and parallel to the second axis and divides the chamber into first and second compartments, axially spaced along the first axis. The port communicating with the chamber is in the second compartment. The aperture extends through the wall member and connects the first and second compartments. The mounting seat is on the wall member and extends circumferentially about the aperture for removably and replaceably seating an element with a selected pressure seal to the wall member.

Abstract: A pressure transmitter apparatus having a Unitary body portion, separate diaphragms and flange elements and disposed within the body, a first and second normally vertical pressure passage. The first and second pressure passageways communicate respectively between first and second pressure openings extending-normally horizontally through the body portion, and a transducer mounting element. The mounting element, coupled to the body portion and located above the pressure passageways, mounts a transducer that generates a differential pressure signal. One or a pair of diaphragm elements are configured to form first and second process diaphragms, closing first and second pressure openings. The flange element overlies the diaphragm element and is removably and replaceably secured to the body portion.

Abstract: A dual-column, dual-detector gas detector and analyzer employs both a photo-ionization detector and a flame-ionization detector. In a survey mode, samples of ambient air are driven through both detectors, and the outputs of both detectors are used to determine the presence of one or more gasses. In analysis mode, fixed-volume samples of ambient air are driven through two elution columns having different properties. The output of each elution column is fed to one of the detectors. The arrival times of gas peaks at the two detectors are employed to develop two lists of candidate gasses. The lists are cross-checked for the presence of each candidate on both lists. Candidates identified from their presence on both lists are identified. A further check attempts to identify candidates which are identifiable from their presence on one of the lists, and not on the other. Components identified in this way are added to the final list.

Abstract: A double-tuning-fork (DTF) resonator having electrical circuitry operable, if either tine breaks, to develop a characteristic electrical circuit condition which is detected to produce an indication of failure. In one preferred embodiment, the circuitry includes a dual series circuit for energizing the electrodes on the DTF tines, with (1) a first series circuit passing down one tine to the remote end thereof, across the support segment at that end of the DTF, and back up the other tine, and (2) a second series circuit passing down the other tine to the remote end thereof, across said support segment at that end, and back up the first-mentioned tine. If either tine breaks, or if there is fracture of another part of the DTF carrying an electrode energizing lead, vibratory excitation of both tines ceases, and the output signal is caused to go to a level (e.g. zero) clearly indicating failure of the instrument.

Abstract: An interferometer mirror drive system compensates for velocity and tilt errors induced by ambient vibration, as well as providing long-term automatic alignment of the mirrors. A uniquely configured .lambda./8-thick step on the fixed mirror of the interferometer introduces a 90-degree phase shift in one of two reference light beams, to produce quadrature signals which characterize the relative motion between the fixed and the driven mirrors. An electronic circuit extracts velocity and tilt data from the quadrature signals and develops error signals indicative of deviations from the desired coordinates of the moving mirror. The error signals are used to generate a set of control signals which in turn are supplied to an arrangement of drive coils attached to the moving mirror, to restore the mirror to the desired coordinates.

Abstract: A gas chromatograph having a pneumatic detector adapted to produce a component concentration measurement signal that is relatively unaffected by changes in carrier flow rate. The detector includes an orifice connected in the flow stream at the output end of the chromatographic column to produce a pressure signal responsive to density. This orifice signal also responds to flow rate of the fluid passing through the column. A capillary is connected in series with the orifice to produce a second flow-responsive pressure signal which is subtracted from the orifice signal in a way to effectively eliminate changes in the final measurement output signal due to changes in flow rate while leaving the signal variations due to changes in density, i.e. concentration.

Abstract: An all-pneumatic process chromatograph having a pneumatically-actuated sample-injection valve, an orifice connected in the column output line to develop a pressure signal corresponding to fluid density, a pneumatic amplifier for strengthening the pressure signal, and pneumatically-operated control means for developing a periodic sample-valve actuating signal and for selecting a particular peak of interest at a controllable time following injection of the sample. The pneumatic control means includes means automatically operable to adjust the time of peak selection in response to changes in actual peak elution time. The temperature-sensitive elements of the apparatus are contained in a chamber which is heated by a source of steam heat, with the rate of heat transfer being regulated pneumatically to maintain a relatively constant temperature within the chamber.

Abstract: A gas chromatograph having a pneumatic detector adapted to produce a component concentration measurement signal that is relatively unaffected by changes in carrier flow rate. The detector includes an orifice connected in the flow stream at the output end of the chromatographic column to produce a pressure signal responsive to density. This orifice signal also responds to flow rate of the fluid passing through the column. A capillary is connected in series with the orifice to produce a second flow-responsive pressure signal which is subtracted from the orifice signal in a way to effectively eliminate changes in the final measurement output signal due to changes in flow rate while leaving the signal variations due to changes in density, i.e. concentration.

Abstract: An all-pneumatic process chromatograph having a pneumatically-actuated sample-injection valve, an orifice connected in the column output line to develop a pressure signal corresponding to fluid density, a pneumatic amplifier for strengthening the pressure signal, and pneumatically-operated control means for developing a periodic sample-valve actuating signal and for selecting a particular peak of interest at a controllable time following injection of the sample. The pneumatic control means includes means automatically operable to adjust the time of peak selection in response to changes in actual peak elution time. The temperature-sensitive elements of the apparatus are contained in a chamber which is heated by a source of steam heat, with the rate of heat transfer being regulated pneumatically to maintain a relatively constant temperature within the chamber.

Abstract: A flame ionization detector adapted for use in hazardous areas and for mounting in any attitude, capable of using as small a flame as can be dependably maintained because of an arrangement of the flame at the open end of a thin-walled small diameter tubular electrode inside a relatively long open ended cylindrical collector and the regulation of the rates of flows which make it possible to maximize the sensitivity of the detector to the presence of an organic vapor. Excess air is maintained at a predetermined minimum. The inside diameter of the collector is made approximately twice the visible diameter of the widest point of the flame. A curtain of air flowing at a predetermined rate through the annular passage between the electrode and collector is directed into encompassing contact with the flame and the proximity of the collector to the flame maintains a relatively dense ion bearing layer of gases at the surface of the collector.