Abstract: The invention relates to a swivel adapter-coupler that is to be positioned between a conventional fixed drop elbow on the end of a hose of a tanker truck for an underground storage tank. The other end of the swivel adapter-coupler attaches to the pipe adapter (either the fill pipe or the vapor pipe) of the underground storage tank, in the conventional quick-connect type connection. The swivel adapter-coupler permits loops and kinks in the hose to be removed by rotating the swivel adapter-coupler in the proper direction. Likewise, the invention relates to a rotatable drop elbow to replace the conventional fixed drop elbow at the end of a hose on a tanker truck. The rotatable drop elbow eliminates loops and kinks in the hose by merely rotating the drop elbow in the proper direction.

Abstract: A pressure control system for accurately controlling the pressure of the air in a discharge line during a pneumatic offload includes a blower, a supply of pressurized air and a pressure relief valve. The blower directs a stream of air into the discharge line to produce a positive air pressure. The pressure relief valve includes a valve body defining a hollow valve chamber, a valve positioned within the valve chamber and a valve seat opposite the valve. The valve chamber of the pressure relief valve is in fluid communication with the discharge line through a first inlet port and in fluid communication with the supply of pressurized air through a second inlet port that receives air from the supply of pressurized air. The valve chamber of the pressure relief valve is also in fluid communication with the ambient atmosphere through at least one outlet port.

Abstract: A system and method ensures that the wet lines of a bottom loading petroleum cargo tank remain free of hazardous liquid during transit. The system and method continuously monitor and automatically purge liquid that collects in the wet lines during transit, for example from a leaking emergency valve. The system includes a liquid sensor positioned at a low point in the wet line, a low pressure purge controller in electrical communication with the liquid sensor and a solenoid valve in electrical communication with the purge controller. The system further includes a one-way flow valve in flow communication with the solenoid valve and the wet line. The solenoid valve is also in flow communication with an external source of compressed gas, such as the air system of the cargo tank or an auxiliary air supply. Preferably, the system further includes a remote warning indicator for indicating to the operator of the cargo tank that a particular wet line is leaking excessively.