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Tone test (Ultratone )
The Tone Test is an ultrasonic method for non-destructive testing which is used when it is difficult to
pressurize or draw a vacuum in a system. This ultrasonic test is applicable to a wide range of items,
including:
CONTAINERS, TUBES, PIPES, HEAT EXCHANGERS, WELDS , GASKETS, SEALS, DOORS,
WINDOWS, OR HATCHES.
The test is conducted by placing an ultrasonic transmitter, called TONE GENERATOR, inside (or on
one side) of the test item. The warble pulse-signal from the TONE GENERATOR will instantly "flood"
the test item and penetrate any existing leak hole. Depending on configuration and material, even thin
spots in certain metals can be vibrated by the signal. By scanning for sonic penetration on the
exterior surface (or opposite side) of the test item with the Ultraprobe, the leak will be detected. It will
be heard as a high pitched warble, similar to bird chirping.
The Tone Test incorporates two basic components: a TONE GENERATOR (an ultrasonic transmitter),
and the Scanning Module in the Ultraprobe. To conduct the test:
1. Make certain the test item has no fluids or contaminants such as water, mud, sludge, etc.,
that can block the path of the transmitted ultrasound.
2. Place the Tone Generator within the container, (if it is a room, door or window to be tested,
place the Tone Generator on one side pointing in the direction of the area to be tested) and
close, or seal so that the Tone Generator is enclosed within.
NOTE:
The size of the test area will determine the amplitude selection of the Tone Generator. If the
item to be tested is small, select the LOW position. For larger items, use the HIGH position.
3. Scan the test area with the Ultraprobe as outlined in LEAK DETECTION procedure. (i.e., start
with the sensitivity selection at 0 and proceed down). When positioning the Tone Generator,
place the transducer facing and close to the most crucial test area. If a general area is to be
checked, position the Tone Generator so that it will cover as wide an area as possible by
placing it in the "middle" of the test item.
How far will the sound travel? The Tone Generator is designed to cover approximately 113m³ (4000
cubic feet ) of uninterrupted space. This is slightly larger than the size of a tractor trailer. Placement is
dependent upon such variables as the size of the leak to be tested, the thickness of the test wall and
the type of material tested (i.e. is it sound absorbant or sound reflective?). Remember, you are dealing
with a high frequency, short wave signal. If the sound is expected
to travel through a thick wall, place
the Tone Generator close to the test zone, if it is a thin metallic wall, move it farther back and use
"low". For uneven surfaces it may be necessary to use two people. One person will move the Tone
Generator slowly close to and around the test areas while another person scans with the Ultraprobe
on the other side.
