Hitachi E-U Series Instruction Manual page 12

(b) Models; VB-004(S)E-U to 110-E2
The flange size of Vortex Blower is
shown on the table below. Please
see the illustration to the right
(Fig. 3.5) detailing how to properly
connect the thread pipe to the
Vortex Blower. Inspect for any
leaks after installation.
MODEL
VB-004(S)E-U
VB-007(S)E-U
VB-019(S)E-U
VB-030E-U
5. Bypass Hole Installation
For an application where the Vortex Blower
may be operated in a small airflow range
outside the operable range, provide a
bypass hole near the suction or discharge
port of the Vortex Blower (see illustration to
the right). This enables the Vortex Blower
to operate within the operable range by
adjusting the valve in the bypass hole.
6. Changeover Valve Installation
In the event that the starting frequency of the Vortex Blower is too high, the motor
temperature will rise due to the starting current. The starting torque will cause a developing
clearance in the tolerances between the impeller and the shaft, which can lead to motor
burnout or impeller contact (this will affect the life of the ball bearing).
During unavoidable intermittent operation, a changeover valve system can be installed to
prevent this event from occurring (see the illustrations below).
To operate the Vortex Blower without the changeover valve system, please contact the local
Hitachi distributor.
Intermittent air requirements
VB
Thread pipe
(Supplied by customer)
Flange Connection Sizes
B
NPSC１1/4
NPSC１1/2
NPSC１1/2
NPSC 2
Open
Valve
Close
- 12 -
Fig. 3.5 Pipe connection
MODEL
VB-040-E2
VB-060-E2
VB-080-E2
VB-110-E2
Bypass Hole
Valve
VB
Suction
Intermittent suction or discharge requirements
Valve
VB
B
Flange
B
NPSC 2
NPSC2 1/2
NPSC 3
NPSC 3
VB
Discharge
Suction
Discharge