－10－
3.3
Vacuum piping
(1) Before connecting the pipe to the pump, clean the inner walls of the vacuum chamber,
piping and vacuum valve to completely eliminate moisture, fine particles, dust, dirt
and rust.
(2) Show general exhaust system in figure 2.
Between vacuum chamber and the pump, figure 2 please attach , stop valve (A) and leak
valve (B).
(3) Backflow preventer
A backflow preventer is incorporated into the pump to prevent the oil from flowing back
while the pump is stopped.
The countercurrent prevention mechanism of the oil is taken in in this pump. As of a pump
stop, it is effective for the prevention of the countercurrent of the oil. （It is not
countercurrent prevention mechanism of the gas.）
The countercurrent prevention valve opens and closes a countercurrent prevention valve
with the oil pressure of a hydraulic pump taken in to a vacuum pump under an air inlet.
As of a pump stop, the check valve closes. The vacuum pump oil prevents an inflow to the
upper part than an inlet port. Besides, the vacuum pump becomes the atmospheric pressure.
But it is not a thing to guarantee the 100% of movement.
Figure 2. Basic piping diagram to the vacuum chamber
Vacuum Chamber
Leak valve (B)
Stop valve (A)
Pump
