BOLTSCOPE PRO
- Bolt Tension Monitor
99
Temperature Factor. The important thing to note is that both the thermal
expansion and the velocity are changing with respect to changes in temperature.
The
BOLTSCOPE PRO
always measures a fastener at 68
F. If the temperature
of the fastener is currently being measured at 108
F, the
BOLTSCOPE PRO
will
compensate, or correct, the measurement back to 68
F. Note: This is an
arbitrary temperature range only. The primary thing to consider is to use a
respectable temperature range with at least 5 different temperature points. The
following procedure outlines the process for experimental determination of the
Temperature Factor for a bolt made of a specific material type and geometry.
Required Equipment.
A means of varying and measuring the temperature of the sample
bolts between 48
to 108
F to an accuracy of +/- 2
F. The device
must allow for a transducer to be connected to one end of the bolt for
the purpose of measuring.
Many sophisticate temperature chambers are commercially available,
and ideally suited for this function. However, a simple and
inexpensive method can be achieved by immersion of the sample
bolts in a water bath, which can be heated to boiling or cooled by
adding ice. At sea level this will reliably vary the bolt temperature
between approximately 48
to 108
F depending on water purity and
atmospheric pressure. By measuring the temperature of the stirred
water bath with a precise mercury thermometer, while reading the
ultrasonic length of the bolt, accurate calibration points can be
obtained.
A
hydratight
BOLTSCOPE PRO
Ultrasonic Bolt Tension Monitor.
A minimum of three sample bolts, which are representative of the bolt
type and geometry for which the Temperature Factor is to be
determined.
NOTES:
The hydratight
BOLTSCOPE PRO
must be calibrated, or zeroed, as
described in the procedure entitled Measuring System Zero in Chapter 8.
The sample bolts should be left to soak at the measured temperature points
for a period of not less than 20 minutes, to insure that temperature is uniform
throughout the sample.
If a water bath is used, care must be taken to avoid immersion of the
ultrasonic transducer.
