Technical
The velocity of ultrasonic energy pulses travelling in a solid material are related to the density and elastic properties of the material. The pulse velocity is thus a measure of density and elastic properties of the material.

In transmitting ultrasonic energy through a coarse grained material such as concrete, ceramics or wood, it is necessary for the wave length of energy to be greater than the diameter of the largest grain particle. If it is not, all of the energy will be reflected back by the particles and none will reach the receiver.

Typically, the 150 KHz transducers are used for ceramic testing – the signal wave length is about 1.4 inches (34mm). Finer materials require higher frequencies for opti-mum resolution.

The basic Ultrapulse™ System contains a transmitter, a receiver and a very accurate high speed electronic clock. The transmitter generates an electrical pulse, which when applied to a transmitting transducer, converts the electrical energy into a pulse of ultrasonic mechanical vibration. This vibration is coupled with the speciman under test by placing the transducer in contact with the speciman. At another selected point on the speciman another receiving transducer is coupled by mechanical contact. Each transmitted pulse of energy registers on the high speed clock. The first energy wave reaching the receiving transducer is converted back to an electrical signal and turns off the clock. The elapsed time is displayed on the LCD in 0.1 microsecond increments.

The large LCD display has a graphic display of waveform in the lower half of the LCD with option for displaying the envelope of the received signal or expanded front end of the signal.

The hand-held terminal is an external input device; it facilitates input of:

• Distance between transducers.
• English or Metric Units.
• Density differences.
• Moisture correction.
• Selection of P or S wave transducers.

Enabling the following to be done automatically:

• Calculation of ultrasonic pulse velocity
• Calculation of Poissons Ratio
• Calculation of modulus of elasticity
• Finally, the hand-held terminal with RS-232 adaptor
• enables stored data to be uploaded to a P.C.