Abstract: A microprocessor controlled, general purpose gene synthesizer for programmably synthesizing selected nucleotide sequences. Depending upon a programmed chemistry, metered volumes of selected bases and reagent/solvents are sequentially metered into the bottom of a reaction cell containing solid-supported nucleotides, where desired linkages are achieved in an agitated suspension. Self-refilling syringe metering and electrically initiated, pneumatically operated valving insures economical, non-contaminated synthesis. Preprogrammed, selectable chemistries and operator programmed sequences are operatively coupled under microprocessor control to ensure a general purpose synthesizer.

Abstract: A temperature controller for monitoring the temperature of a rotating heating system and regulating the temperature relative to a desired temperature. A transmitter within the rotating system coupled to a remote stationary controller via slip rings produces a magnitude varying current control signal within a calibrated range at a magnitude proportional to the sensed temperature. A pair of voltage dividers within the transmitter establish the level and range of current magnitude relative to a constant current source. The remote stationary controller compares the current control signal to a set-point and synchronously supplies power to the heater elements of the rotating system, so long as the sensed temperature is below the desired temperature.

Abstract: A temperature control system for a liquid chromatographic column includes a thin film heater/sensor comprising a foil-like patterned heating element adhesively mounted between a pair of flexible electrically insulative layers. A patterned foil-like temperature sensing element is also coextensively adhesively mounted between the insulative layers in temperature sensing relationship to the heating element. The thin film heater/sensor is wrapped around the chromatographic column and is uniformly compressively secured in contact therewith by a spirally tubularly wound length of flexible wrapping. A remote temperature sensing element controls the heat output of the heating element a linear proportional fashion, thereby maintaining a predetermined temperature gradient over the length of the column. A pre and post-column heaters may be similarly wrapped with a thin film heater/sensors so as to appropriately control the temperature of the liquid entering or leaving the column.

Abstract: A heater roll in which a resistor-type heater mounted in the roll is controlled by use of a temperature sensing element also located in the roll. Electrical power, particularly AC power, is provided through slip rings and the set point for the temperature control is determined by a signal from a current source applied through the slip rings. The set point transmitter is designed to provide a constant current signal to the temperature regulator, irrespective of resistance variations which may be introduced by changes in the slip ring characteristics. As such, the temperature regulator maintains a predetermined temperature in the rotating roll, irrespective of slip-ring resistance variations.