This configuration leads to opening of the solenoid valve provided 
on the oil outlet line. As the oil is extracted the oil-water 
interface in the chamber eventually rises above the bottom 
electrode thereby decreasing the resistance in the sensing 
circuit. This results in a voltage across the resistor, which 
when amplified closes the solenoid valve and thus stops the 
oil extraction. The feasibility of the system will be determined 
by testing it on the experimental model of the separator. 
Alternative means of sensing the oil-water interface may 
be employed in the foregoing control system. Use of an ultrasonic 
transducer, although expensive, can sense the oil-water interface 
precisely. Another means of sensing which can be used is based 
upon the photo-electric principle. Irrespective of the type 
of sensing used, the basic design of the control system remains 
unchanged. 
COMPARISON WITH THE TYPICAL PARALLEL PLATE SEPARATORS 
It was learned from the feasibility tests that a separating 
device based upon the Coanda-effect principle is capable of 
gross separation only. Therefore, for an evaluation the separator 
should be compared with typical, laminar flow parallel plate 
separators. 
Because of its design configuration and the flow velocities 
through it, the Coanda-effect separator will have a considerably 
smaller physical size. For instance, a separator to treat 20 
gpm of oil-water flow rate can be 1.5 feet long x 1 foot wide 
x 1.5 feet high; whereas typical parallel plate type separator 
[1] of the same flow capacity occupies 3 feet--3-1/2 inches 
x 3 feet--6 inches x 1 foot 7 inches of space. The physical 
size comparison of the Coanda-effect separators with typical 
parallel plate type separators for handling 20 and 100 fpm 
of mixture flow rates is given in Table 2. Because of its smaller 
size, for a given flow rate, the equipment cost of the Coanda- 
effect separator will be lower. 
Presently, the Coanda-effect separator is in its early 
stages of development and thus many design modifications are 
required, therefore, a comparison of its oil separating capabilities 
with that of the fully developed parallel plate separator is not 
possible. More work is required before such a comparison can 
be made. Finally, because of the simplicity of its design, 
the maintenance of the separator promises to be easier. 
