Seven runs were made with the system Penn. Ref. Co. "Supersol" (dispersed) water (continuous) to investigate the effects of pulse frequency, amplitude plate spacing, volume flow ratio, and throughput on backmixing, using the technique of continuous injection of a tracer solution into the packed section. Backmixing was found to be surprisingly insensitive to all the above variables over the range studied with the exception of pulse amplitude and continuous phase flow rate, showing greatest dependence on the later. Backmixing increased with decreasing continuous phase flow rate and increased with pulse amplitude.

A pile gas leak detection system consisting of a purchased mass spectrographic type of helium detector, a long sampling line for use in remote or relatively inaccessable locations, a pump to pull a continuous sample of gas from the tip of the probe to the detector, and a rotameter to measure the gas flow rate in the sampling line has been developed, calibrated, operationally tested. The system is practical for use in locating all pile gas leaks larger than about 0.1 cubic foot per hour.