Abstract: Fluid control systems for controlling machine tool operations or other automated mechanical devices. An unlimited number of multiple function systems can be assembled from a basic simple function system employing two-way relay valves which, in their normally blocked state, have a "controlled leakage" venting feature effective to prevent any leakage to outlet and possible system malfunction. This controlled leakage venting feature is constructed so that the leakage path is never exposed to line pressure when a valve changes state from blocked to passing or vice-versa. Fluid memory can also be built in the system. Simple relay valves, limit valves, pressure control relay valves, time delay relay valves and other variations in spool and slide form provide controlled leakage.

Abstract: Fluid control systems for controlling machine tool operations or other automated mechanical devices. An unlimited number of multiple function systems can be assembled from a basic simple function system employing two-way relay valves which, in their normally blocked state, have a "controlled leakage" venting feature effective to prevent any leakage to outlet and possible system malfunction. Fluid memory can also be built in the system. Simple relay valves, limit valves, pressure control relay valves, time delay relay valves and other variations in spool and slide form provide controlled leakage.