Product Overview

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Boiler micro-bubbles
Micro-bubbles are
formed continuously
on the surface
separating the water
from the combustion
chamber due to the
fluid temperature.
This air, carried by the
water, collects in the
critical points of the
circuit from where it
must be removed.
Some of this air is reabsorbed in the presence of colder surfaces.
Steel models
Steel flanged models come standard with a side drain valve (A) to drain
large amounts of air when filling the circuit and to remove any debris
present above the water level.
A drain valve (code NA39753) can be connected (B) at the bottom of the
steel flanged DISCAL
®
to drain collected dirt particles.
Cavitation and micro-bubbles
Micro-bubbles
develop where
the fluid velocity
is very high with
the corresponding
reduction in pressure.
These points are
typically the pump
impeller and the
valveport.
These air and vapor
micro-bubbles, the
formation of which is
enhanced in the case
of non de-aerated
water, may subsequently implode due to the cavitation phenomenon.
Operating principles
The DISCAL
®
air separator is
used to continuously remove the
air contained in hydronic circuits
of heating and cooling systems.
The air discharge capacity is
very high. They are capable of
removing automatically all the air
present in the system down to
micro-bubble level with low head
loss due the special internal
shape of the separator body.
Flow direction of the DISCAL
®
air
separator is bidirectional; flow in
either direction is permitted.
The air separator uses the
combined action of several
physical principles. The active
part consists of an assembly
of concentric mesh surfaces
(1). These elements create the
whirling movement required to
facilitate the release of micro-
bubbles and their adhesion to
these surfaces.
The bubbles, fusing with each
other, increase in size until the
hydrostatic thrust overcomes
the adhesion force to the mesh.
They rise towards the top of the
unit from which they are released
through a float-operated
automatic air vent, with stainless
steel float guide pin (3).
Combustion chamber
wall
Boundary layer
Average water
temperature
Boundary layer
temperature
FLAME WATER
Micro-bubbles
Flame temperature
Wall temperature
Pressure
Velocity
Cavitation
micro-bubbles
Pressure Velocity
Implosions
Valve port
Fluid vapor
pressure
1
2
3
551 compact series
NA551 vertical series
551 and NA551 steel series
551 brass series