Patent attributes
An apparatus includes two pumps and a circuit-changing valve connected to two cooling circuits, with the valve being controlled by a pressure differential created by the pumps. This simplifies controls, reduces components of the pumping system, and also provides a backup pump for each system. The valve's spool is controlled so that when the first pump is started before the second pump (or it generates a higher fluid pressure), the valve causes the two pumps to be connected in a serial arrangement with fluid being pumped through the first circuit and then through the second circuit. But when the second pump is started before the first pump, the valve causes the two pumps to be connected in a parallel arrangement so that the first pump moves fluid only through the first circuit, and the second pump moves fluid only through the second circuit. The valve includes an anti-dithering device.
