sound made by the microswitch can serve as an adequate cycling indication
during the absence of a pilot light.
(2) The fan provides reliable performance for 2 to 5 years under favorable
conditions of temperature and vibration without the necessity of oiling. Its life is
inversely proportional to these factors. For example, at 110,F, the fan may be
expected to give reliable performance in excess of 5 years. If used in ambients of
excessive heat, fan life may be extended by periodic oilings (a small amount once
4. CONSTANT TEMPERATURE BATHS (See figure 16). (See figure 14).
a. The hot and cold baths (with accessories) are supplied as part of the secondary
reference set. The hot bath has a range from ambient to 500,F. The medium most used in
the hot bath is a silicone based oil. The temperature of the bath is adjustable throughout
its range through the use of calibrated controls located on the bath. The bath has a ready
light that comes on when the pre-set temperature has been reached.
b. The cold bath is designed for continuous operation over the temperature range of from
-40,F to ambient using a 60% by volume solution of ethylene glycol in water as a bath
medium. Temperature control is achieved by bucking a constant cooling capacity with a
variable heat medium. High heat transfer rates and minimum temperature gradients result
from the unique action of the dual jet-impeller stirrer employed to agitate the bath
medium. Five heat capacities are available to provide optimum control at the desired
operating temperature and may be selected by means of a heat switch located on the front
of the bath housing.