unigreen
17
5
BLOWER GROUP
All the mistblowers have a high speed fan rotor. You must take great
care and beware of the effects that this can provoke: such as the
aspiration and projection of foreign bodies which, although of a small
size, can be very dangerous especially for the eyes and face.
5.1
MULTIPLIER - FAN UNIT
The Airdrop range is fitted with two versions of a Ø500 centrifugal fan: STD
(max absorption 30 HP) and XP (max 50 HP).
The transmission of the drive from the pump to the fan is done through a
multiplier with one or two gears, plus neutral.
Normally the rotation speed of the fan is 3240 RPM in first gear and 3620
RPM in second in the 2-speed multiplier (multiplied ratios 1:6 - 1:6.7) with the
power takeoff running at 540 RPM.
You can change from one gear to the next with the lever on the multiplier,
made accessible through the opening on the side in the rear left part of the
machine or at a distance on the right side. The lever has 2 or 3 positions
depending on the number of gears and the central position is neutral (to use
only the pump without the fan).
WARNING: the gear change lever must only be used with the power-takeoff
disengaged and the fan stopped. If it is difficult to engage, turn the cardan
shaft slightly by hand to find the right position of the lever (make sure the
tractor is turned off).
For the maintenance of the multiplier (see point "Multiplier Lubrication"
5.5
CLUTCH
Fans have a centrifugal type clutch that makes it possible to engage the fan
rotor gradually.
This prevents jerky starts, due to the inertia of the fan rotor, which can have a
negative effect on the transmission.
For the centrifugal clutch to work properly the speed of the power-takeoff
mustn’t be less than 450 rpm, especially if you are using the first gear of the
multiplier.
Generally clutches with shoes/plates made of sintered material with a high
coefficient of friction are fitted, on some low power models rubber clutches
may be fitted.
WARNING! As there is a high multiplication ratio, the fan must be started
gradually. Suddenly engaging the power-takeoff clutch (at high speed) can
damage the gears.
Ø500 Nylon impeller with sinterized expansion
clutch.
Ø500 fan with multiplier, 2-speed plus
neutral.
WORK TEMPERATURE
Heat is generated by the friction between the
various moving components and on the basis
of the power transmitted. The temperature
of the multiplier or disengaging box depends
on the capacity to dissipate heat to the
surrounding environment and therefore the
surfaces involved in the heat exchange and
the environmental conditions.
The specifications refer to environmental
conditions with a temperature between
-10° +50°C (14°C -122°F).
The working temperature limit of the box
is 90°C (200°F) established to prevent the
ageing of the seals and guarantee a sufficient
viscosity of the oil. The heat makes the air in
the box expand and therefore increases the
pressure inside. The correct use of the oil
seals is guaranteed up to an internal pressure
of 0.5 bar. Boxes designed to be used for
particularly heavy duty work are equipped
with a breather cap that can be fitted
on any cast iron box on request.
