Abstract: An apparatus for controlling the metering of additives which are to be blended with a primary substance includes an element which determines how much additive is being discharged from an additive storage container. This element includes a weight detecting device which detects a first portion of the additive contained in a metering container and includes another weight detecting device for detecting the weight of a second portion of the additive contained in an inventory container which feeds the additive into the metering container. This element also includes a volumetric flow rate monitoring device for monitoring the flow rate of a liquid additive. Each of these detecting and monitoring devices generates respective electrical signals proportional to the respective monitored conditions. The apparatus also includes an element for sensing how much of the primary substance is being discharged from a primary substance container.

Abstract: A method and apparatus for monitoring conditions in a fluid flow path so that the composition and operation of the flow path can be determined is disclosed. The apparatus includes a fluid flow detector, such as a gas flow logging tool, which detects the velocity at which a fluid, such as a gas, flows along the fluid flow path, such as a gas injection conduit used in a gas lift program for extracting oil from a well. The monitoring apparatus also includes a pressure detector and a temperature detector. Each of these detectors provides a respective electrical signal to a recorder unit, such as a strip chart recorder, for creation thereby of respective logs. The logs generated by the recorder unit permit qualitative and quantitative analyses of identifiable fluid flow path phenomena, such as the locations of valves and the volumetric flow of the fluid, to be made.