A grounding device for a roll-out electrical component is provided. Preferably, the stream to be separated is fed to the present process in a substantially gaseous phase. The replacement piston has a cross sectional area smaller than a cross sectional area of an original piston of the pump. Therefore, the effectiveness of the heat dissipation can be enhanced without increasing the thickness of the device and such that the need for heat dissipation in a portable electronic device of higher performance and computing power can be satisfied.