VALVE SYSTEM AND ARRANGEMENT FOR ON-LINE VALVE REPLACEMENT

摘要

Several embodiments are disclosed of an automatic shutoff valve apparatus for permitting removal, repair, or replacement of a control valve from a mounting base without deactivating a complete system. In addition, a redundancy arrangement is disclosed wherein the shutoff valve apparatus and at least two control valves are employed in parallel so that the device activated by the control valves can be maintained operative when one control valve malfunctions or is removed, repaired, or replaced.