Abstract: A cooling apparatus for an electronic system, includes a coolant tank, main pumps, heat exchangers, a common supplementary pump, and supplementary check valves. The coolant tank temporarily stores a coolant. The main pumps are respectively arranged in a plurality of heat generators in the electronic system, and the main pumps supply the coolant from the coolant tank to the heat generators. The heat exchangers cool the coolant from each of the heat generators and return the coolant to the coolant tank. The common supplementary pump is operated when any one of the main pumps has failed and supplies the coolant from the coolant tank. Each of the supplementary check valves has an upstream side connected to an outlet port of the supplementary pump and downstream sides connected to outlet ports of the main pumps. Each of the supplementary check valves is opened when a pressure difference between the upstream side and the downstream side of each of the supplementary check valves is larger than a predetermined value.

Abstract: A liquid cooling apparatus includes a heat exchanger, a tank, leakage sensors, first and second level sensors, a timer counter, and a control section. The heat exchanger cools a coolant to be supplied to a heat generating portion in an electronic device. The tank temporarily stores the coolant cooled by the heat exchanger before the coolant is supplied to the electronic device. The leakage sensors detect leakage of the coolant in a circulation path for repeatedly performing cooling and heat absorbing operations. The first and second level sensors detect a decrease in amount of the coolant in the tank. The timer counter counts a time interval between the instant at which a leakage detection output is output from one of the leakage sensors and the instant at which a coolant decrease detection output is output from one of the first and second level sensors. The control section stops an operation of the electronic device when a value of the timer counter is a predetermined value or less.