Abstract: A self-contained downhole apparatus for being lowered into an oil or gas well to internally record samples of at least one environmental condition comprises three body sections linearly and releasably interconnected. One of the body sections is a selected one of a plurality of transducer housing sections. The selected transducer housing section is mechanically and electrically connected to a second body section containing microcomputer-operated signal processing circuitry. The third body section contains a power supply.

Abstract: A self-contained memory gauge includes either semiconductor or magnetic core memory for retaining downhole information related to sampled parameters, such as borehole temperature and pressure. A microprocessor-based computer manages the power utilization by independently and selectably energizing and de-energizing different sections of the gauge. The magnetic core memory is tested for operability, and the addressing of the magnetic core memory is adjusted in accordance with any inoperable memory locations. Samples of the monitored environmental conditions can be taken at variable rates dependent upon software monitoring of the condition, the remaining battery life and the remaining memory capacity and in response to hardware monitored pressure changes. Each sample can be taken to a selectable resolution. A watchdog circuit monitors the microprocessor to insure that it is operating within a preselected time limit.

Abstract: Lead sources, and particularly lead sulfide concentrates, are halogenated utilizing a halogen gas in a dry atmosphere at a relatively low temperature to selectively halogenate the lead. The process is improved by effecting the halogenation in a fluidized state in a fluidized bed reactor, the fluidized state of the lead sulfide being accomplished by introducing a mixture of halogen gas and an oxygen-containing gas at a rate sufficient to maintain the lead sulfide in the desired fluidized state. Thereafter, metallic lead may be obtained by leaching the halogenated mixture with brine, filtering to separate elemental sulfur and residue from soluble lead halide. The soluble lead halide is then crystallized and the desired metallic lead is obtained by fused salt electrolysis.