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4.4 Backflow preventer(G-101S)
A backflow preventer is incorporated into the pump to prevent the oil from flowing back while
the pump is stopped.
The backflow preventer actuates in the case of an emergency including power failure. So, after
the pump is stopped due to a power failure, follow the procedures mentioned in “
4.3 Stopping
the operation
” to stop the operation.
① To stop the pump, always close vacuum valve (A) and then open leak valve
(B). If this procedure is neglected, the pump oil fills the cylinder,
making restart difficult or causing damage to the pump. The pump oil also
may flow back to the vacuum chamber side.
② If vacuum valve (A) is not closed, air may leak into the device side through
the pump increasing the pressure.
4.5 Thermal protector
A manually reset thermal protector is incorporated in the motor in order to interrupt the power
circuit of the motor and prevent damage to the motor when an over current flows through the
motor due to a stop in rotation or overload resulting from the pump malfunctioning during
operation. The type of thermal protector to be used depends on the pump model.
Table 3 Characteristics of the thermal protector
Operating characteristic
Model
Operation
temperature
The temperature
that can reset
1φ,100V
100℃±7℃
74℃±7℃
G-101D,G-101S
1φ,200V
100℃±7℃
74℃±7℃
When thermal protector operates, at first I disconnect the plug, and please inform our company.
The motor is very hot when the thermal protector has actuated. Never touch it with your hand.
When the cause of the malfunction has been eliminated, check that the motor has cooled down,
and then press the manual reset button to restart operation (see “
6.5 Trouble check list
”).
Firing hazard. As the surface of the pump body is higher temperature(70～80℃)
during operation, do not touch it until cooled down after stopping the pump.
4.6 Gas ballast valve(G-101D)
The pump is equipped with a gas ballast valve in order to evacuate vapor and condensable gases
such as solvent vapor.
Evacuated condensable gas that liquefies in the compression and pressurization processes of the
pump is mixed with the pump oil and starts circulating through the pump together with the oil.
In such a case, the same effect as when oil of a high steam pressure is used is produced, and the
ultimate pressure of the pump increases. Moreover, the lubricity of oil deteriorates and the
service life of the shaft seal is shortened.
If air or dry nitrogen enters through the gas ballast valve just before the compression and
Note
Caution
