BLADE
8-3
TI215G0010
How to use the machine
MODULATION
All MATTEI compressors are fitted with an automatic
system for adjusting pressure according to delivery
pressure. The internal pressure of the compressor
depends (partly) on line pressure and, consequently, on
the demand for air; when the latter drops or is nil, line
pressure and internal pressure increase.
In Mattei compressors, the maximum pressure at which
the unit runs no-load can be set (by calibrating a valve).
For values slightly below maximum, the suction valve is
only “partially” closed by suitably modulating machine
capacity to line requirements. Maximum pressure and
values slightly below this define a field or range which is
known as a
MODULATION BAND
.
This operating mode exploits this potential. The control
unit ignores the Pmax and Pmin settings and operates
the compressor without stopping except in case of an
operator command.
F
NOTE
The modulation bandwidth is typically 0.3 bar.
Suppose maximum no-load pressure is set (using
the SERVO-VALVE) to 7.3 bar.
– For pressure values lower than 7 bar (7.3 - 0.3 =
7), the compressor delivers 100% of its capacity;
– For values ranging from 7 to 7.3 bar (the
modulation band), the compressor delivers
less than its rated capacity, suitable for line
demand.
MODULATION
MODULATION
ON LOAD
MODULATED OFF LOAD
Pservo
Pnom
t
MODULATION
BAND
