Introduction General Description - Ransburg 75785 Service Manual

REA-90 and 90L Spray Applicators - Introduction
INTRODUCTION INTRODUCTION INTRODUCTION
INTRODUCTION INTRODUCTION
GENERAL DESCRIPTION GENERAL DESCRIPTION GENERAL DESCRIPTION
GENERAL DESCRIPTION GENERAL DESCRIPTION
The REA process is an air-atomized method for
electrostatically applying coatings to objects. The
REA applicator system (technology) applies a
high voltage DC charge to the applicator electrode,
creating an electrostatic field between the atomizer
and the target object.
The REA-90 or REA-90L Delta Electrostatic Spray
Applicators (see Figures 1 and 2) applies a -85kV
DC charge to the coating materials at the point of
atomization. This electrostatic charge allows a
more efficient, uniform application of coating
material to the front, edges, sides, and back of
products. It is highly suitable for applying coatings
to a variety of surface configurations: large targets,
small parts, tubular wares, concave and recessed
parts, etc. Because it is a grounded fluid system
(for solvent based systems), it is highly suitable
for applying a wide range of solvent reduced
coatings such as enamels, lacquers, epoxies,
etc. The 75786 and 75982 models are available to
accommodate waterborne materials.
The REA-90 and REA-90L electrostatic spray
applicators are transformable between air spray
and HVLP spray technology. The REA-90 is
designed for use as a conventional air spray (high-
pressure) or high volume/low-pressure (HVLP)
air spray to atomize the coating material. By
changing a select few parts, the applicator may be
transformed to be operated in either spray mode.
(See "Spray Technology Conversion Procedure"
in the "Installation" section for details.)
A regulated pressure fluid system delivers coating
material to the atomizer. At the time of triggering
the applicator, fan and atomization air is introduced,
which atomizes the coating material into a spray
mist. The atomized spray particles under the
influence of the electrostatic field become
electrically charged. The charged particles are
attracted to, and deposited on, the target object.
The forces between the charged particles and the
grounded target are sufficient to turn most normal
1 1 1 1 1 1 1 1 1 1
overspray around and deposit it on the back
surface of the target. Therefore, a high percentage
of the coating is deposited on the target.
One of the many features of the REA applicator
system is that the electrical energy, which is
available from the resistive charging electrode, is
limited to the optimum level of safety and efficiency.
This system is incapable of releasing sufficient
electrical or thermal energy during normal operating
conditions to cause ignition of specific hazardous
materials in their most easily ignited concentrations
in air (see NFPA-33).
The control unit provides low voltage output to the
applicator and contains controls for AC on/off,
high voltage adjust, kV and micro amp meter.
As the applicator electrode approaches ground,
the control unit and applicator circuitry cause the
high voltage and current to "fold back" and decrease
towards zero for models 75785, 75979, and 75982.
For models 75786, the fold back circuitry in the
control unit has been turned off to provide maximum
voltage for waterborne applications.
W A R N I N G W A R N I N G W A R N I N G
W A R N I N G W A R N I N G
! ! ! ! !
Never use a standard solvent base
>
applicator system (75785 or 75979) on a
standard waterborne control unit. Failure
to comply may cause damage to equip-
ment and/or risk of fire and injury.
W A R N I N G W A R N I N G W A R N I N G
W A R N I N G W A R N I N G
! ! ! ! !
Never use a waterborne (75786 or
>
75982) REA-90 system to spray solvent
reduced coating materials. Failure to
comply may cause damage to equipment
and/or risk of fire and injury.
AH-94-04.7