Abstract: A solenoid controlled valve is mounted in a threaded opening of a pressure vessel which contains compressed natural gas. The valve includes a valve body having a head, which is exposed outside of the pressure vessel, and a neck, which is located within the pressure vessel. A solenoid poppet valve is mounted to the inner end of the neck. A valve seat is mounted in a bore within the valve body. An orifice at an inner end of the valve seat exposes a flow passage between the bore of the valve body and an outlet port, which is located in the head of the valve body. The solenoid poppet valve includes a seal for closing the orifice, a bias spring which biases the seal toward the seat to close the orifice, a plunger which is connected to the seal, and a solenoid coil which, when energized, moves the plunger so that the seal moves out of engagement with the seat and permits flow of compressed gas from the interior of the pressure vessel to the outlet port.

Abstract: A method and apparatus for detecting and analyzing errors in a communications system is described. The method employs expert system techniques to isolate failures to specific field replaceable units and attempts to restore the failing unit to service by removing it from service, resetting the resource and returning it to service if it passes retesting. The expert system techniques include detailed decision trees designed for each resource in the system. The decision trees also filter extraneous sources of errors from affecting the error analysis results.