Multiquip ST70 - Manual (Page 28)

PAGE 28 — ST-70 — PARTS & OPERATION MANUAL — REV. #4 (05/29/07)
7. The shuttle tube is plugged if volume at the discharge end
of the hose stops, the hose is soft and the hydraulic oil
pressure gauge reads 3000 psi or more.
To clear a plug in the shuttle tube, great care must be taken
as a dangerous condition will exist from pressure build-up
inside the shuttle tube. (With the shuttle valve, the concrete
can be pumped in reverse.)
WARNING: NEVER PLACE YOUR HANDS
OR ANY PART OF YOUR BODY IN THE
HOPPER OR ALLOW ANYONE ELSE TO DO
SO.
Follow these instructions carefully:
7.1 DO NOT open any of the delivery system joint clamps.
7.2 Switch the pump into “Reverse”:
With pump speed at medium-slow (approx. 12 strokes per
min.) try to pull the “pack” back into the hopper with 5 or 6
reverse strokes, remix the concrete in the hopper.
Switch the pump into “Forward”.
If it is still plugged, repeat “Reversing” procedure three
times.
If concrete still does not move, see 7.3 and 7.4 below. The
last action MUST be “pumping in reverse” to relieve the
pressure in the shuttle tube.
7.3 Stop the pump. Switch off the engine.
7.4 The senior or most experienced operator must warn all
others to stand at least 20 feet away from the machine and
turn their heads to face away from the pump.
The operator will position himself/herself beside the
reducing elbow at the pump outlet, then, wearing safety
glasses slip the end of a pry bar (24" length of reinforcing
steel rod) under the latch of the hose clamp and flip it up.
Carefully knock the end of the hose away from the reducer.
Chip the concrete out of the reducer with the pry bar.
Remove the reducer.
From the discharge end chip the concrete out of the shuttle
tube with the pry-bar. If concrete cannot be loosened from
the outlet of the shuttle tube, then remove the clean-out plug
on the bottom of the hopper, discharging the concrete.
Only the senior operator may then remove the inspection
cover plate from the shuttle tube, by using a long extension
wrench and the 24" pry bar. Make sure the accumulator
pressure gauge reads zero prior to removing cover.
3. Damaged hoses with internal restrictions can cause
blockages.
4. If a blockage occurs in the hose, STOP the pump, “walk the
hose” until you find the point of trouble. (The hose will be
soft immediately past the blockage.) Elevate the hose at
that point with the blockage hanging down. Using a hammer,
you can pound the down stream edge of the packed area
until it free flows or shakes out of the hose. Pumping can
now be resumed. If this method does not clear the pack
FOLLOW THE INSTRUCTIONS IN Section 7, paragraph
7.1 thru 7.5 of this page.
5. “Down-hill pumping” can be difficult. When the pump is
stopped, the material can flow slowly and cause the hose to
collapse. When pumping is resumed, you can expect a
blockage at the point of hose collapse. To prevent this, the
hose can be “kinked off” at the discharge end when the
pump is stopped, to stop gravity flow. The use of stiffer mixes
when pumping down-hill will stop gravity flow.
6. When pumping vertically:
6.1 When pumping vertically up the side of a building,
above 40 feet, we recommend the installation of steel pipe
securely fastened at intervals as necessary to support the
pipe. Ninety-degree, long-radius pipe sweeps should be
installed at the top and bottom of the steel line. Use a 25 ft.
hose, or short section, off the pump. For the balance of the
horizontal distance to the vertical line, use pipe. This type of
installation has been satisfactory on many jobs being
pumped in excess of 100 feet high. Line pressures are
always less using steel pipe as compared to hose.
6.2 When pumping vertically using all hose, it is
recommended not to go higher than 50 feet with hose. The
hose should be tied off at intervals of 10 feet, if possible.
Special attention should be given when tying the hose off at
the top as the hose will have a tendency to stretch when
filled with concrete. This will increase the possibility of a
blockage at the point where the hose is tied off. To avoid
this, a long radius 90 degree elbow is recommended. The
suggested place to tie off is under the clamp coupling that
connects the hose to the 90 degree elbow.
Note: It is strongly recommended that pipe be used
on all vertical pumping for safety and convenience. If
it is absolutely necessary to use hose, then use
section 6.2 as a guide.
ST-70 — OPERATING PROCEDURES