Humboldt H-4340 Sand Equivalent Test Set with Case - Manual (Page 8)

4. Allow the wetted specimen and cylinder to stand undisturbed for 10 ± 1 minute.
5. At the end of the 10 minute soaking period, stopper the cylinder: then loosen
the material from the bottom by partially inverting the cylinder and shaking it
simultaneously.
6. After loosening the material from the bottom of the cylinder, shake the cylinder and
contents by any one of the following three methods:
• Mechanical Shaker Method: Place the stoppered cylinder in the mechanical sand
equivalent shaker, set the time, and allow the machine to shake the cylinder and the
contents for 45 ± 1 second.
• Manual Shaker Method:
A. Secure the stoppered cylinder in the three spring clamps on the carriage of the
hand-operated sand equivalent shaker and reset the stroke counter to zero.
NOTE 8: To prevent spillage, be sure the stopper is firmly seated in the cylinder before
placing in the manuaI shaker.
B. Stand directly in front of the shaker and force the pointer to the stroke limit
marker painted on the backboard by applying an abrupt horizontal thrust to the
upper portion of the right-hand spring steel strap. Then remove the hand from
the strap and allow the spring action of the straps to move the carriage and
cylinder in the opposite direction without assistance or hindrance.
C. Apply enough force to the right hand spring steel strap during the thrust portion
of each stroke to move the pointer to the stroke limit marker by pushing against
the strap with the ends of the fingers to maintain a smooth oscillating motion.
The center of the stroke limit marker is positioned to provide ihe -proper stroke
length and its width provides the maximum allowable limits of variation. The
proper shaking action is accomplished only when the tip of the pointer reverses
direction within the marker limits. Proper shaking action can best be maintained
by using only the forearm and wrist action to propel the shaker.
D. Continue the shaking action for 100 strokes.
• Hand Method:
A. Hold the cylinder in a horizontal position and shake it vigorously in a horizontal
linear motion from end to end.
B. Shake the cylinder 90 cycles in approximately 30 seconds using a throw of
9 ± 1 in. (229 ± 25 mm). A cycle is defined as a complete back and forth motion.
To shake the cylinder at this speed properly, it will be necessary for the operator
to shake with the forearms only, relaxing the body and shoulders.
7. Following the shaking operation, set the cylinder upright on the work table and
remove the stopper.
8. Irrigation Procedure:
• During the irrigation procedure, keep the cylinder vertical and the base in contact
with the work surface, Insert the irrigator tube in the top of the cylinder, remove
the spring clamp from the hose, and rinse the material from the cylinder walls as
the irrigator is lowered. Force the irrigator through the material to the bottom of
the cylinder by applying a gentle stabbing and twisting action while the working
solution flows from the irrigator tip. This flushes the fine material into suspension
above the coarser sand particles.