Miniature multistation photometer rotor temperature control

Claim 1

In a compact analytical photometer of the rotary cuvette type, a temperature detector and control system for maintaining the rotor of said photometer at a desired temperature comprising a thermistor mounted in said rotor near one of the cuvettes thereof, a positive voltage source connected to said thermistor, a current-to-voltage converter connected to the output of said thermistor, a voltage amplifier connected to the output of said converter, a meter connected to said amplifier for providing an indication of the temperature of said rotor, a comparator, a temperature adjustment reference potentiometer, the output of said voltage amplifier and output of said potentiometer connected in opposition to each other and as a combined input to said comparator, a radiant heat lamp positioned adjacent to said rotor for supplying heat thereto, and means connected between the output of said comparator and the input to said lamp for amplifying any output signal from said comparator for powering said lamp as long as there is any difference in the input voltages to said comparator, said reference potentiometer adapted to be preset to exactly nullify the detected temperature signal from said thermistor when said rotor is at said desired temperature, whereby said system automatically maintains said rotor at said desired temperature.

Claim 4

The method of maintaining the temperature of the rotor cuvettes in a rotary cuvette photometer at a desired value above ambient temperature comprising the steps of supplying radiant heat from a single source to a rotor containing said cuvettes, detecting the temperature adjacent one of said cuvettes, generating a first electrical signal proportional to said detected temperature, generating a second electrical signal proportional to the temperature desired to be maintained in said cuvettes, generating a third electrical signal proportional to any difference between said first and second signals, and controlling the radiant heat supplied to said rotor in accordance with said third signal to maintain said temperature at said desired value above the ambient temperature to which said photometer is exposed.

Claim 5

The method of maintaining the temperature of the rotor cuvettes in a rotary cuvette photometer at a desired value above ambient temperature comprising the steps of supplying radiant heat from a single source to a rotor containing said cuvettes, detecting the temperature adjacent one of said cuvettes, generating a first electrical signal proportional to said detected temperature, generating a second electrical signal proportional to the temperature desired to be maintained in said cuvettes, generating a third electrical signal proportional to any difference between said first and second signals, and controlling the radiant heat supplied to said rotor in accordance with said third signal to maintain said temperature at said desired value above the ambient temperature to which said photometer is exposed.