Valve arrangement with at least two diaphragms

An oil pump unit that comprises a pump housing having an end plate, pump means within said housing that has an inlet and an outlet for pressurizing oil, and inlet port, an outlet port, fluid circuit means for placing the inlet port in fluid communication with the pump means inlet and the outlet in fluid communication with the outlet port and return excess oil back to the pump inlet, a plurality of valve means in the circuit means for controlling the flow of oil through said circuit means, a cover removably mounted by the housing to in cooperation therewith define an interior chamber, and having a plate shaped portion that in part defines the interior chamber and is axially spaced from the housing end wall, said cover including said inlet and outlet ports, said valve and circuit means in part being defined by said cover, a plate shaped common component and an elastic valve plate, said valve plate and common component being located in the chamber axially between the end plate and the cover plate-shaped portion with the valve being axially between the common component and the plate-shaped portion, and means for forming a fluid seal between the end plate and said common component, said common component having a first side surface portion that has a plurality of valve seats and an annular channel surrounding each valve seat and flat surface parts surrounding said channels, an axial opposite second side surface portion that is in fluid sealing relationship with the fluid sealing means and has a plurality of oil passage grooves, an axial first passage for each valve seat that opens through the respective seat and to a groove, an axial second passage opening through the first side portion and to one of the grooves and a third passage for each channel that opens to the respective channel and to a groove other than the one that the first passage in the valve seat it surrounds opens to, the valve plate abutting against the plate shaped portion and having a plurality of axial valve plate passages that respectively open to the common component second passages, a diaphragm section for each valve seat that is movable between a condition blocking oil flow between the respective first passage and the channel that surrounds it and alternately to a condition permitting such oil flow, the diaphragm unit having for each diaphragm section a raised circular bead portion of a larger diameter than the respective channel that is retained in fluid and sealing engagement with the adjacent common component flat surface part and surrounds the respective diaphragm section, said valve means including separate means for mechanically biasing the respective diaphragm section to its oil flow blocking condition.