1. Field of the Invention
The present invention relates to a cooling apparatus for a liquid-cooled electronic system.
2. Description of Related Art
Conventional cooling apparatuses for cooling electronic systems circulate a cooling liquid in a liquid-cooled electronic system such as a computer to cool the load. One of the conventional electronic system cooling apparatuses, for example that disclosed in Japanese Non-examined Patent Publication No. 61-125634, for example, normally has two units of pumps for supplying the cooling liquid, one for normal use and the other in standby mode for taking over the cooling operation when the former fails. Thus, providing the two units of pumps makes it practical to put the standby unit in the operating state if the normally operating unit fails for continued cooling.
However, in the prior-art systems, the cooling apparatus cannot be serviced when the electronic system such as a computer being cooled is in operation. To be specific, the prior-art electronic system cooling apparatus has a controller for controlling the operation of the pumps and valves. Any attempt to service the controller, such as upgrading the controller, requires the operator to stop the controller which halts the entire cooling apparatus because the cooling apparatus of the prior art has only one controller, making it impractical to service the cooling apparatus while it is in operation.
Recently, there is a strong demand for an around-the-clock operation capability for such cooling apparatuses that cool electronic systems, including computers, such as large main frame computers. However, the prior-art apparatuses cannot satisfy this requirement by reason of the above-mentioned problem.