6
Figure 1 illustrates that the air
moves not between the rotors but
between the rotors and the side
of the housing. Also, the machine
is bi-directional, meaning that the
direction of rotation of the blower
can make either side the inlet or
discharge. See also the Flow
Direction by Rotation section on
below.
No attempt should ever be made
to control capacity by means of
a throttle valve in the intake or
discharge piping. This will increase the power load on the drive system, increase operating temperatures,
and can overload and/or seriously damage the blower. Likewise, if a possibility exists that fl ow to the blower
inlet may be cut off during normal operation of a process, then an adequate vacuum relief valve must be
installed near the blower. A pressure type relief valve in the discharge line near the blower is also strongly
recommended for protection against cutoff or blocking in this line. Check valves should also be used on
every blower when more than one blower is connected to a discharge line. This is for both safety and
operating conditions.
When a belt drive is employed, blower speed, if necessary, can usually be adjusted to obtain desired
capacity by changing the diameter of one or both sheaves, or by using a vari-speed motor pulley. In a
direct coupled arrangement, a variable speed motor or transmission is required, or excess air or gas may
be blown off through a manually controlled unloading valve and silencer. Gas units can use bypasses, but
some applications may require additional cooling. If there is a large volume of high pressure air or gas
downstream of the blower, a check valve in the piping downstream of the blower will protect the blower from
overspeeding in a backward direction upon shutdown.
Consult your Tuthill Vacuum & Blower Systems sales professional if questions arise.
4.1 FLOW BY DIRECTION AND ROTATION
WARNING
Refer to diagrams in this manual for proper rotation and orientation in inlet
and discharge.
Figure 2 - Flow Direction by Rotation
INTAKE
INTAKE
DISCHARGE
INTAKE
DISCHARGE
HORIZONTAL FLOW
VERTICAL FLOW
DISCHARGE
INTAKE
DISCHARGE
INTAKE
DISCHARGE
RIGHT DRIVE
CW ROTATION
LEFT DRIVE
CW ROTATION
LEFT DRIVE
CCW ROTATION
RIGHT DRIVE
CCW ROTATION
TOP DRIVE
CW ROTATION
TOP DRIVE
CCW ROTATION
BOTTOM DRIVE
CW ROTATION
BOTTOM DRIVE
CCW ROTATION
DISCHARGE
INTAKE
INTAKE
INTAKE
DISCHARGE
DISCHARGE
Figure 1 - Illustration of general operation principle
INLET
INLET
INLET
DISCHARGE
DISCHARGE
DISCHARGE