Abstract: A platform shaker for use in a CO2 rich environment that has a corrosion resistant output shaft and a corrosion resistant, sealed motor casing. An eccentric drive assembly is connected between the output shaft and a platform and has components treated with a corrosion inhibiting coating. A shaker control controls the electric motor has components treated with a conformal coating.

Abstract: A block heating system includes a housing defining an open-top well closed at the bottom by a base plate which is heated by an electric heater in the housing. One or more carrier blocks are removably received in the well, each block having a plurality of receptacles in the top face for receiving test tubes or the like to be heated. A temperature probe assembly includes a rigid metal sheath projecting up into the well from the base plate and receivable in a bore in the bottom of one of the carrier blocks. A thermistor at the tip of the sheath senses the temperature in the middle of the block, which is displayed on an LED display on the front panel of the housing.

Abstract: A temperature-controlled environmental chamber includes a resistance heater powered through a first solid state relay and a refrigeration unit including an electrically powered thermally controlled suction throttling valve connected in the refrigerant line between the evaporator and the inlet of the compressor, and including a bimetal motor and a heating element therefor powered through a second solid state relay. A thermostat senses the temperature in the chamber and compares it to a set point temperature and outputs a pulse-width modulated control signal indicative of the difference between the two temperatures. The control signal directly controls the heater relay for substantially continuous variation of the heater between minimum and maximum heating conditions.

Abstract: A temperature-controlled environmental chamber includes a resistance heater controlled by a solid state relay and a refrigeration unit including an electronically controlled suction throttling valve connected in the refrigerant line between the evaporator and the inlet of the compressor. A temperature controller senses the temperature in the chamber and compares it to a set point temperature and outputs a pulse-width modulated control signal indicative of the difference between the two temperatures. The control signal directly controls the heater relay for substantially continuous variation between minimum and maximum heating conditions. The control signal is converted to an analog signal for controlling the throttling valve of the refrigeration unit for substantially continuous variation between maximum and minimum cooling conditions, so that the amount of cooling provided is inversely proportional to the amount of heating provided.

Abstract: The apparatus may be used to control heater elements for an over chamber. The heater elements are operated in accordance with the output of a comparator having on one input a voltage representative of the temperature in a chamber. The voltage on the other input is established in accordance with the desired or ultimate temperature in the chamber. As long as the volage on the second-mentioned input is greater than the voltage on the other input, the heater elements will be energized to heat the chamber. The voltage on the second-mentioned input is modulated with a triangular wave so that the heater elements are operated intermittently as the desired temperature of the chamber is approached. The amplitude of the triangular wave varies with the desired temperature so that at higher and higher oven temperatures, the heater elements start to become intermittent at higher and higher temperatures.