Abstract: An oxidant flow conduit having a restriction and branching downstream of the restriction to provide a primary flow conduit for supplying oxidant to a nebulizer and an auxiliary flow conduit having an adjustable valve for supplying oxidant to a mixing chamber is provided. A differential pressure transducer measures the pressure drop across the restriction to provide an output signal. A primary fuel conduit is provided having a pair of restrictions with an adjustable valve for supplying fuel to the mixing chamber. A boost conduit having a restriction is connected to the primary fuel conduit and between the restrictions providing for supplementing the fuel to the mixing chamber when a different fuel mixture is used. A differential pressure transducer measures the pressure drop across the pair of restrictions to provide an output signal. A square root linearization operation is performed on each signal in a microprocessor and modified output signals drive respective fuel and oxidant digital displays.

Abstract: There is described a programmable gas flow control apparatus for use in atomic absorption spectroscopy. Essentially, an all pneumatic system is described which provides for a predetermined flow of fuel and oxidant to the burner. The invention compensates for the variation in oxidant flow due to nebulizer adjustments by adjusting the oxidant flow to the auxiliary inlet of the burner. The invention utilizes a pneumatic computing relay which senses the oxidant flow to the nebulizer and simultaneously adjusts the flow to the auxiliary inlet so that the total flow of oxidant satisfies the predetermined optimum rate. The constant monitoring of the nebulizer line by the computing relay allows for continual adjustment of the oxidant flow to offset subsequent adjustments.

Abstract: An automatic fluid sampling transport system for use in fields such as atomic absorption spectroscopy and liquid chromatography. The system described provides for circular tray sampling having an increased through-put capacity. This is accomplished by providing a system which allows the sampling of vials in concentric circles on the same carousel. The mechanism described synchronizes the raising and lowering of the sample probe to the incremental, rotational movement of the carousel and the rotational movement of the probe carrying means between successive sample vials in the various concentric circles. The mechanism is relatively simple and is adaptable to provide a plurality of such concentric circles of openings to expand the through-put capability of the system.

Abstract: Power is applied to an electrical element in maintaining a thermal system at stabilized conditions and a feedback signal is derived to control the electrical input to the heating element by linearly combining functions of the current through the heating element and the voltage drop thereacross respectively. In one embodiment, each of the linearly combined functions in the feedback signal can be varied independently to change the stabilized conditions of the thermal system, while in another embodiment a microprocessor is incorporated to provide such variation for a sequential range of stabilized conditions.