Water pump having water cooling device

摘要

A water pump includes a housing having a water inlet, a water outlet, an exit and a mouth. A circulating water passage couples the exit to the mouth of the housing. A pump may pump water from the exit to the mouth of the housing via the circulating water passage. The housing includes two ducts communicating with each other and communicating with the mouth, and the water inlet and the water outlet respectively. Two plugs are slidably disposed in the ducts for switching water to circulate through the exit and the circulating water passage when the water outlet is closed.