Helium Bottle Pressure Measurement by Portable Ultrasonic Technique

摘要

The report details the application of a portable ultrasonic method to accurately check the pressure in a helium bottle. The subject helium bottle provides an initial launch boost to the Short Range Attack MIssile's (SRAM-A, or AGM-69A) hydraulic flight control system. The method described would apply to any pressure vessel, with minor variations from those procedures and equipment detailed in the report. A series of tests was conducted at the Boeing Aerospace facility in Kent, Washington on a SRAM-A helium gas bottle, to determine the feasibility of measuring gas pressure within the helium bottle by ultrasonic technique. The method, based on measurement of the speed of ultrasonic waves transmitted through a medium at constant pressure and temperature, provides the ability to determine bottle pressure without the necessity of removing the bottle from the missile. This bottle had previously been used for pressurizing the Flight Control Actuation System. The ultrasonic waves were introduced into the bottle by a transducer attached to one side of the gas bottle and received by a transducer attached 180 directly opposite the input transducer. The amplitude of the ultrasonic signal decreased with decreasing pressure, proving that the method was feasible. The process was further developed leading to the successful use of a single ultrasonic transducer placed on the side of the bottle, at any convenient location, to transmit and receive the ultrasonic signals passing through the medium. Keywords: Pressurization, Ultrasonic tests, Pressure measurement. (sdw)