Interim Report on the Development of an Air Pulser for Pulse Column Application

Abstract

This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, "person acting on behalf of the Commission" includes any employee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor.

Design of Air Pulsers for Pulse Column Application

“…The pulse amplitude falls off at the higher frequencies. This effect was not noted in earlier work, because of the assumption of a square wave pressure function (Weech et al, 1961). Referring to Figure 4, it is obvious that as the cycle time is shortenedi.e., the exhaust valve is opened sooner-less area will be retained under the pressure curve and this results in the "falloff" of column pulse amplitude at higher frequencies.…”

“…Previous solutions (Weech et al, 1961) assumed that the pressure-time relationship in the air system could be approximated by a known wave shape, either square or sinusoidal. Examination of the pressure recordings presented in this reference plus those measurements made at the NFS plant indicate that this assumption is valid for low frequencies, but measured and computed values disagree more widely using these assumptions as frequencies increase.…”

Chemical and Process Development Branch Annual Report, Fiscal Year 1965

“…Initial development work at the ICPP covered the analog simulation and testing on a 10-inch diameter column [26,27]^ This work has now been extended to three additional extraction columns having diameters of 1.31, 2.07, and 3.07 inches. When testing the air pulsers on these plant columns, provisions were made to obtain experimental data by temporarily substituting rigid plastic tubing for the stainless steel pulse legs.…”

“…With thel.31-inch-diameter column, a deviation of 30 percent was noted. A study of the original mathematical model [27] and the solutions obtained from the analog computer disclosed that the friction term contained the source of error; specifically, the part of the friction term which expresses the pressure drop due to flow through the sieve plates in the pulse column appeared to be the source of error.…”

“…In the original mathematical model [27], the pressure drop due to flow through the sieve plates was expressed by a modified orifice formula, using a constant orifice coefficient of 0.68. While it was recognized at the time that this value was only approxim,ate, pulse amplitudes obtained from the analog computer solutions closely checked the amplitudes measured on the 10~inch column; and, consequently, a more sophisticated mathematical model was considered to be an unnecessary refinement.…”