Self suctionpump is used for the first time, need to add water, then don't need to add water.
自吸式水泵第一次使用时，需要加引水，以后则不必再加引水。
2
A suctionpump used to create a partial vacuum.
用于使局部真空的抽吸泵。
3
While the candle burns, a suctionpump pulls in the surrounding air to a simple mechanism that separates the carbon black - a byproduct of combustion - from the rest of the air.