GLOSSARY of TERMS as used throughout this manual.
Ambient: The environment surrounding the dehydrator. Ambient factors which can infl uence a dehydrator include the
temperature, the relative humidity, the atmospheric pressure and quantity of various pollutants which are present.
Desiccant: The component within the dryer towers which is used alternately to retain, then to expel moisture from the
process air. Dielectric dryers employ desiccant which is totally inert, that is; it undergoes no chemical or physical change
in normal use.
Dew Point: Expressed in
0
F. , t
he temperature at which dew or frost would form at 14.7 PSIA. The dew point of a given
air sample rises with increased pressure. In 1943 Dielectric established a dew point of -40
0
F. as standard for their com-
pressor/ dehydrators and for the pressurization of the communications equipment which they produce. NOTE: -40
0
is
the one point at which the Fahrenheit and Celsius scales are numerically equal.
Heatless Dryer: A dryer design of Dielectric which describes the most simple and effi cient heatless air dryer. A dryer
consists of two desiccant towers, two maintenance free ball checks and two direct acting solenoid valves controlled by
a solid state timer. The main air fl ow is handled by the ball checks without measurable pressure loss. Only the purge air
fl o ws through the two way solenoid valves, providing high effi ciency and long trouble free service.
Elevation: The distance which the installation site is above sea level expressed in feet, used interchangeably with alti-
tude.
Line Pressure: The pressure of the low pressure outlet system, which is controlled by adjustment of the line pressure
regulator, is displayed on the line pressure gauge and is monitored by the adjustable low and high pressure alarm switch-
es.
Prime: To prepare the dehydrator system for operation by fi lling it with water, to the proper level and in a specifi ed man-
ner.
PSIA: Pounds per Square Inch Absolute. The measure of the pressure of a gas or liquid, expressed in pounds per square
inch, relative to a total vacuum. Standard atmosphere at sea level equals 14.7 PSIA (approx.) or 0 PSIG.
PSIG: Pounds per Square Inch Gauge. The measure of the pressure of a gas or liquid within a component or system,
to the degree it is greater than that of the surrounding atmosphere, expressed in pounds per square inch. The internal
pressure as shown on the gauges used on air dryers.
SCFD: Standard Cubic Feet per Day. A rate of air fl ow measured in cubic feet at 14.7 PSIA and 68
0
F. One SCFD when
subjected to 10 PSIG (without temperature c
hange) would occupy a space equivalent to 0.6 cubic feet.
Segregated Alarm: An alarm circuit which provides separate terminations for each alarm function within the dehydrator.
Segregated alarms can provide to a remote location the information necessary for establishment of maintenance priorities.
Segregated alarm terminations which close in alarm are standard on the RE series dehydrators.
Std. conditions: Standard operating conditions imply a reasonably clean environment at 70
0
F.( 21
0
C.) a
nd sea level. Ambi-
ent conditions impact dryer maintenance needs.
Summary Alarm: An alarm which does not identify an individual condition, but which indicates an active state of one
or more alarm sensors within the dehydrator. Alarm terminations which close in alarm and separate terminations which
open in alarm are standard on the RE series dehydrators. The close-in-alarm terminals may optionally be equipped with
resistors at installation if preferred.
System Pressure: The pressure at which the compressors and the drying towers (desiccant towers) operate. System
Pressure determines the quantity of compressed air fl ow, the quantity of purge air and the moisture load on the desiccant
towers.
42
APPENDIX H
To Next Page
Loading...