Accession Number:

AD0276393

Title:

Summary Report, 1 October 1958-30 September 1961.

Corporate Author:

TEXAS UNIV AUSTIN DEFENSE RESEARCH LAB

Report Date:

1961-09-30

Abstract:

WORK WAS CONCERNED WITH DEVELOPMENT OF ACOUSTIC FILTERS TO ATTENUATE LIQUID-BORNE NOISE IN PIPING SYSTEMS. THE FILTERS BUILT AND TESTED ARE SPECIFIED AND THE LABORATORY TESTS ARE DESCRIBED. THE TEST DATA INDICATE THAT BOTH SIDE BRANCH AND EXPANSION CHAMBER FILTERS PRODUCED SIGNIFICANT ATTEN1ATIONS IN SOME FREQUENCY BANDS IN FLOW TESTS WITH THE FILTERS INSTALLED IN A LABORATORY PUMPING SYSTEM. AT A PUMP SPEED OF 1700 RPM THE MAXIMUM DIFFERENCE BETWEEN RELATIVE OUTPUT-IMPUT LEVELS IN HALF-OCTAVE BANDS FOR A 203 IN. LONG PIPE AND FOR A DOUBLE EXPANSION CHAMBER FILTER WAS FOUND TO BE 28 DB MEASURED IN THE 106-150 C BAND. THE CORRESPONDING DIFFERENCE FOR A 183 IN. LONG PIPE FOR ANOTHER DOUBLE EXPANSION CHAMBER FILTER WAS 32 DB MEASURED IN THE 106-150 C BAND. THE CORRESPONDING DIFFERENCE FOR A 183 IN. LONG PIPE FOR ANOTHER DOUBLE EXPANSION CHAMBER FILTER WAS 32 DB MEASURED IN THE 212300 C BAND. AN INSTRUMENT EVELOPED TO MEASURE ACOUSTIC IMPEDANCE IN LIQUID-FILLED PIPES IS DESCRIBED. RESULTS OF PRELIMINARY IMPEDANCE MEASUREMENTS ON SHORT WATER COLUMNS ARE SHOWN. SOUND PRESSURE MEASUREMENTS OF A SUPPLEMENTARY NATURE, MISCELLANEOUS EXPERIMENTAL WORK TOWARD DEVISING MEANS FOR QUIETING PUMPING SYSTEMS, AND CONSTRUCTION OF SPECIAL DEVICES AND EQUIPMENT ARE ALSO DESCRIBED

Pages:

0001

Identifiers:

Modernization Areas:

Contract Number:

NOBS77033

File Size:

0.00MB

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