Product Overview

Function
The AUTOFLOW
®
device has to guarantee a constant flow rate when its upstream/downstream pressure differential varies.
It is therefore necessary to refer to the ∆p - flow rate diagram and to a basic diagram illustrating the operation methods and the relevant
variable effects.
Operating principle
The regulating element of these devices is composed of a cilinder and a piston with side fixed and variable geometry orifices, through which
the fluid flows. These orifices are governed by the piston movement, pushed by the medium thrust. A specially calibrated spring counteracts
this movement.
Autoflows are high performance automatic regulators. They regulate selected flow rates within a very tight tolerance (approx. 10%) and offer a
wide range of operation.
In this case, the regulating piston
remains in equilibrium without
compressing the spring and gives
the fluid the maximum free flow area.
In practice, the piston acts as a fixed
regulator and thus the flow rate
through the AUTOFLOW
®
depends
solely on the differential pressure.
If the differential pressure is contained
within the control range, the piston
compresses the spring and gives the
medium a free flow area to permit
regular flow at the nominal rate for
which the AUTOFLOW
®
is set up.
In this case, the piston fully compresses
the spring and leaves only the fixed
geometry aperture for the medium to
pass through.
As in the first case above, the piston
acts as a fixed regulator. The flow rate
through the
AUTOFLOW
®
thus
depends solely on the differential
pressure.
0,15 bar/15 kPa 2,0 bar/200 kPaDIFFERENTIAL
PRESSURE
FLOW RATE
G
0
Kv
0,01
= 0,258 · G
0
range ∆p 15–200 kPa where G
0
= nominal flow rate
DIFFERENTIAL
PRESSURE
FLOW RATE
0,15 bar/15 kPa 2,0 bar/200 kPa
G
0
Control range
Initial ∆p
Final ∆p
0,15 bar/15 kPa 2,0 bar/200 kPa
Kv
0,01
= 0,070 · G
0
range ∆p 15–200 kPa where G
0
= nominal flow rate
FLOW RATE
DIFFERENTIAL
PRESSURE
G
0
AUTOFLOW
®
devices
Below the control range
Within the control range
Above the control range