Abstract: A manometer type instrument with an open leg above an indicator fluid. It is subject to immersion in a body of liquid, the change in level of which is to be measured. It includes an improvement which eliminates the formation of a capillary seal at the top of the open leg. The improvement uses a relatively thin wire that is supported so as to extend down into the open leg far enough to reach through the capillary seal.

Abstract: A system for concurrently transferring a volatile liquid fuel from a source thereof into a fuel tank, while receiving vapors which are displaced from the tank during the inflow of the liquid fuel. Included in the system is a vacuum assist arrangement capable of imposing a vacuum condition on the vapor return line to avoid passage of vapors to the atmosphere. The liquid phase of the system includes a liquid flow regulator adapted to establish a desirable flow rate. Further, a vapor restrictor interposed in the vapor section of the system includes means to both throttle and regulate the vapor flow whereby to establish a favorable vapor:liquid ratio during normal operation.

Abstract: A system for transferring a volatile liquid fuel into a tank therefor, while avoiding passage of fuel vapors into the atmosphere. Vacuum assist means is provided including a reciprocatory, fuel actuated tandem motor and pump combination, to assure maintenance of a condition in the system which will prompt removal of fuel vapors from the tank being filled.

Abstract: A balanced system for transferring a volatile liquid fuel into a tank therefor, while avoiding passage of fuel vapors into the atmosphere. Vacuum assist means is further provided to assure a tight fit between a removable fuel dispensing nozzle and the tank filler tube.