Electronics LP-24 User Manual

Page 14

Fig. 21 The amount of this curvature,
called arc height, is an indication of
the blast stream intensity and the val-
ue, as measured on a standard Al-
men gage, can be placed into a
standard SPC process control chart.
There are three strip thicknesses, low
intensity (N), medium intensity (A),
and high intensity (C). Most abrasive
blast cleaning is performed at high
intensity with the (C) strip.
An arc height of .005" to .007" was
found to be ideal for this blast clean-
ing application.

Fig 20

Fig 21

Fig. 20 Once the final conveyor speed
and shot flow rate (motor amps) have
been determined, the standard Almen
strip (SAE specification J442) can be
used to check for proper operation.
The Almen strip, shown here, is mount-
ed with four hold-down screws onto a
standard Almen holder that has been
welded into place on the pipe. This is
the industry standard test for the shot
peening and blast cleaning intensity.

The Almen test strip is blasted on one side only and then removed from the holder. Once released
from the hold-down screws the strip will curve.