The dry coupling technique offers a number of considerable advantages. For example when a wide spectrum of transmitted signals is used, many of the geometric considerations conventionally applied in ultrasonic’s can be ignored. Typically, the transmitter and receiver transducers need not be in alignment, they can be oriented at a right angle to each other. This characteristic, plus the fact that the transducer tip can be as small as 5mm diameter, enables testing to be achieved that cannot be dealt with by conventional means.
With the Dryscan technique, highly effective signal transmission can now be achieved by using a completely dry contact system. The ultrasonic energy is coupled between the transducers and the material under test by using special plastic pads on the transducers, eliminating the need for a coupling medium. Transducers can be held or they may be roller type for continuous pass scanning using various manual or automatic manipulation systems, which can be linked to C-Scan recording systems. The Dryscan 410D concept is simple to apply and requires only a minimum of operator training. This technique results in no possible hazards of radiation, contamination or degradation of the test pieces.
Advantages of the System
The main advantages of the Shadow Technique is summarized below:
- No coupling medium is required to contact the transducers acoustically to the test material.
- Many of the geometric considerations applied to conventional ultrasonic detection methods can be ignored.
- The system is highly reliable for fault detection.
- The method can be used for many materials as a GO or NO-GO system – semi – or fully automatic.
- In many cases, materials surface preparation is not necessary.
Test Range: 0 – 1mm (0.05in) up to 0 – 20000 mm (800 in.) at steel velocity. Variable in 1,2,5 sequence or continuously in 1mm (0.05in) increments.
Velocity: 256 to 16000m/s continuously variable.
Probe Zero: 0 to 999.999 μs, continuously variable.
Delay: Calibrated delay from 0 -20000mm in 0.05 mm steps at steel velocity (0-400in. in 0.002 in. steps).
Gain: 0 to 110dB. Adjustable in 0.1, 0.5, 1, 2, 6, 10, 14 and 20dB steps.
Test Modes: Pulse echo and transmit/receive.
Pulser: 100V – 450V square wave pulser. Pulse width from Spike to 2500ns duration – rise/fall times <10ns into 50 ohms at 200V: Width adjustable in 2% of nominal width, minimum 1ns maximum 40ns.
ActiveEdge™ Unique active pulse control for enhanced near surface resolution and signal response.
P.R.F: Selectable 15 to 5000Hz in 5Hz steps.
Update Rate: 60Hz (NTSC Mode); 50Hz (PAL Mode).
Rectification: Full wave, positive or negative half wave and unrectified rf.
Frequency Range: 7 narrow bands centred at 0.25Mhz, 0.5MHz, 1MHz, 2.25MHz, 5MHz, 10MHz and 15MHz. Broad band at 2 MHz to 22MHz (-6dB) and 1MHz to 35 MHz (-20dB). Special Dryscan mode allowing the resonant frequency of the receiver stage of the Dryscan 410 to be adjusted between 150kHz and 1.42MHz in 10 kHz steps.
Mode 1:Signal Monitor
Mode 2:Depth and amplitude of first signal in gate.
Mode 3: Echo-to-Echo distance measurement. (single gate)
Resolution: To 0.01mm (0.001in) for distance measurement or 1% FSH for amplitude measurement. Large display of measurement at top of A-Scan display. Measurement mode selectable between peak and flank.
A-Scan Memory: Maximum of 800 waveforms can be printed or transferred to a PC using optional SDMS software.
Panel Memory: 100 stores for retaining calibrations.
DAC: DAC defined by up to 10 points and digitally drawn on screen. DAC curves meet requirements of EN 1714, JIS and ASME standards, selectable between -2, -6, -10, -12 and -14dB. Amplitude read out selectable between % DAC, % FSH or relative dB.
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* Shipping for international buyers will be invoiced separately from the purchased product due to the high expense of shipping charges.
Warranty: No warranty is expressed or implied with any unit. All sales include a 3 day right of return (ROR). For any reason, within 72 hours of taking possession of the item, the buyer can return the item for a complete refund minus all shipping costs.