Brochure

Operating principle
The air separator is composed
of a set of metal screen surfaces
arranged like spokes (A). This
screen creates a swirling motion
to assist the release of micro-
bubbles and their adhesion to the
metal screen. The bubbles join
and increase in size until the
hydrostatic force increases to
overcome the force of adhesion
to
the screen.
Next, they rise to the top of the
chamber where
they are released
by the float-operated automatic
air vent valve (B).
B
A
The process of air formation
The quantity of air that can remain dissolved in solution in the water
depends on the pressure and temperature.
This is known as Henry’s law. It may be noted that there is a greater
release of air from the solution as the temperature increases and
the pressure decreases. This air is in the form of microbubbles with
diameters of approximately tenths of a millimeter.
The microbubbles form continuously in the water of the solar
heating systems on the top of the panels, because that is the point
in the circuit where the highest temperatures are reached.
A portion of the air is re-absorbed as the medium reaches the parts
of the circuit at a lower temperature. Because air remain the medium
it must be extracted.
System operation
In solar panel heating systems with forced circulation, it is
necessary to expel all the air in the medium during the phases of
start up and operation.
The air separator permits separating and expelling this air from
the fluid continuously and automatically. Any decrease in pressure
due to the release of air is compensated by the expansion tank or
automatic filling unit.
Automatic
filling
T
max
= 160°C / 320°F
P max = 10 bar / 150 psi
T
max
= 160°C / 320°F
P
max = 10 bar / 150 psi
T
max
= 160°C / 320°F
P
max
= 10 bar / 150 psi
T max = 160°C / 320°F
P
max
= 10 bar / 150 psi
Installation
The air separator must always be installed vertically and preferably:
- before the pump to ensure a drop in pressure so microbubbles of
air can develop.
- on the return and in the bottom portion of the solar circuit where
there is no potential for formation of steam.
0.2
4
3
3.5
Δ p (ft of water) (kPa)
1
0.5
0.25 0.30 0.35 0.40 0.45
0.6 0.7
0.8
0.9 1.2
1.4
1.6 1.8 2.5 4.0
4.5
2
3.0
3.5
5
Recommended max. flow
2
10
5
20
6 7 8 9
12
14 16 18
3
3.5
4
4.5 2.5
1.75 1.5 1.25 1.0
0.7
F
(m
3
/h) (gpm)
0.1
0.05
0.09
0.08
0.07
0.06
0.035
0.04
0.045
0.12
0.14
0.16
0.18
0.25
0.3
0.35
0.2
1
0.1
0.2
0.5
0.9
0.8
0.7
0.6
0.12
0.14
0.16
0.18
0.25
0.3
0.35
0.4
0.45
1.2
1.4
1.6
1.8
2.5
2
1
0.5
0.9
0.8
0.7
0.6
0.45
0.4
1.4
1.6
The maximum recommended speed of the fluid in the piping is 4.2 ft/sec,
which is equivalent to a flow rate of 6.5 gallons per minute.
Hydraulic characteristics
T max = 160°C / 320°F
P max = 10 bar / 150 psi
Construction details
Discal air separator is built to permit
maintenance and cleaning operations
without having to remove the valve
body from the pipe.
Access to the moving parts that
control the air vent is attained by
simply removing the top cover.
Resistance to heat and high discharge pressure, allows the maintenance
of the functional features of the air separator with glycol water temperatures
up to 320°F. The internal geometry of
the air separator has been designed
to discharge the air up to a pressure
of 150 psi.