PRESSURISED LEAKS
Applications for pressurised type inspections include compressed air or gas of any kind, air brake systems, pipes/lines,
steam systems, water lines, manifolds, and likewise all vacuum systems (fig.4.). Note: Ultrasonic detection relies on detecting the sounds
associated with the turbulence of the fluid or gas exiting a hole or orifice under a differential pressure. It is independent of the type of
gas or fluid. The receiver will readily detect air and vacuum leaks typically caused by bad gaskets, cracks in pipes, and worn valve seats
(right). As with all new inspection technologies nothing substitutes for the importance of practice in listening to the differences between good
and bad components in their real life "ultrasonic" application.
NON-PRESSURISED LEAKS
Non-pressurised vessels or containers cannot generate ultrasonic sounds. The supplied transmitter is used to broadcast an ultrasonic
noise which is optimised to the frequency response of the receiver. Some examples are: pin hole leaks, tanks, HVAC, seals, windshields,
weather stripping, and whole house integrity.
1.
Turn on the transmitter and place in the enclosed environment to be evaluated. The transmitter will fill the interior with a piercing
warbling sound. Note: Since the output is in the ultrasonic range, you will not hear it without the receiver.
2.
Walk around the exterior of the enclosed environment while sweeping the receiver around the suspect areas (fig.5.). Compromised
areas will be revealed by the change in tone and intensity both audibly and visibly by watching the changes on the LED indicator.
USING THE LED INDICATOR FOR LOCATING LEAKS
Please note that the volume control is independent of the LED indicator. Depending on the amount of ultrasonic signature being detected, you
can use both the level of intensity on the LED indicator and the audible amount of sound through the headphones. As you get closer to the
problem decrease the volume. As the sound gets louder, repeat the process until you have pinpointed the location.
While scanning in a side to side pattern with the receiver, watch the level of the LED indicator. Keep the receiver pointing in the direction of the
highest bar. Please note that with minute leaks, the LED indicator may not move up from the first position. In this situation, use the audible
signal as discussed above.
AUTOMOTIVE MAINTENANCE APPLICATIONS
ENGINE MECHANICAL:
Finding vacuum leaks, you will hear a hissing noise as soon as you point the receiver unit under the bonnet. Place the hollow probe on the
unit and listen and watch the LED indicator and you can pinpoint the location of the leak fast and easily.
Finding engine noises. The receiver will locate those engine noises and let you find where they are truly coming from. Ultrasound does not
transfer within engine components due to the directional characteristics of ultrasound. Use the solid contact probe.
ELECTRICAL SYSTEMS:
Separations in high-tension spark plug wire conductors can be quickly identified from the corona discharge "snapping" sound emitted. The
same applies to arcing within electrical motors and accessories. Also listen to connection points for the "snapping" or "frying bacon" sound.
This is a sound a poor connection makes under electrical load. Circuits are best tested under operation and full load.
The receiver is also good at locating short circuits. Shorts give off a "frying" or "snapping" sound also. As you are checking for shorts or
connection problems, try to wiggle the wiring. Use the hollow probe for this test.
AIR CONDITIONING SYSTEMS:
You can use the unit in one of three ways to find the problem. Use the hollow probe for this test.
1.
Since most faulty Air Conditioning systems will be empty of Freon, pressurise the system with Nitrogen to about 150 to 250 psi and
then listen for the leak using the hollow probe. This method is also great for evaporator leaks inside a car. On really slow leaks,
while the system is under pressure (250psi), spray a soap solution on the A/C components and lines and you will hear the bubbles as
they escape and pop from the system. Most of the time, you can hear them from more than 3 feet away.
2.
You can also pull a vacuum on the system and listen for ultrasound air sucking into the system.
3.
Place the flexible hose onto the transmitter and inject ultrasound into the A/C system. You can inject the sound into the service port
into the system. The short ultrasound wave will escape were the leak is occurring. The ultrasound wave is so short that it will escape
from an opening 1/20th the thickness of a human hair.
IGNITION SYSTEMS:
This is by far the best and quickest method for diagnosing modern Coil Over Plug (COP) systems. You will hear the snapping of the plugs
firing in the headset. After some experience testing ignition systems, you can tell if you have a plug or wire problem by the sound alone. When
checking make sure you listen at both ends of the plug wire if you can to determine the problem area. Use the solid probe for this test.
Fig.4.
Fig.5.
VS919 - 2 - 160306
