초록 ▼

Measuring the distance to a surface of an object using ultrasonic energy pulses, an ultrasonic energy pulse is directed toward the object and the time is measured for the reflection to return so as to determine the distance to the object. A reference ultrasonic pulse is directed through a fixed and

Measuring the distance to a surface of an object using ultrasonic energy pulses, an ultrasonic energy pulse is directed toward the object and the time is measured for the reflection to return so as to determine the distance to the object. A reference ultrasonic pulse is directed through a fixed and known distance to provide a reference measurement. To enhance the accuracy of the measurement, the air in the region traversed by the ultrasonic pulses is mixed by directing a swirling flow of air in this region so that the temperature of the air in the path of the reference measurement is more nearly representative of the temperature of the air where the distance measurement is taken.

대표청구항 ▼

A test apparatus for accurately measuring the distance through an ambient fluid to a surface, comprising: distance measurement means carried by the test apparatus and oriented toward the surface for measuring the time required for an energy pulse to be transmitted to and reflected back from the surf

A test apparatus for accurately measuring the distance through an ambient fluid to a surface, comprising: distance measurement means carried by the test apparatus and oriented toward the surface for measuring the time required for an energy pulse to be transmitted to and reflected back from the surface; reference measurement means carried by the test apparatus and mounted for measuring the time required for an energy pulse to be transmitted a fixed distance so as to thereby provide a reference measurement to compensate for changes in the speed of travel of the energy pulse due to temperature changes; and means for mixing the ambient fluid in a zone between the surface and said reference measurement means so that the temperature of the fluid in the path of said reference measurement means is more nearly representative of the temperature adjacent said surface.