Multiquip Mayco Concrete Pump LS600 - Manual (Page 33)

MAYCO LS600 PUMP — OPERATION AND PARTS MANUAL — REV. #4 (9/15/11) — PAGE 33
The use of 2 -1/2” I.D. hose in these extreme cases reduces
line pressures or the addition of slight amounts of water to
the mix, if permissible, will permit easier pumping. The use
of certain pumping admixtures may help.
If excessive pulsation exists in the hose, it is advisable to
use burlap or some means of wear protection under the
hose at points where the hose may wear through the outer
cover; e.g. over forms, steel or sharp curbs.
SNAP-JOINT COUPLINGS
When using Snap-Joint couplings with gaskets to join hose,
see that they are washed clean after each job. Keeping the
hose ends clean (heavy duty) is very important for the best
job setup. A thin coat of grease on the rubber gasket or
dipping both coupling and gasket in water before coupling
the hose will make for easier installation.
NEW PUMPS
All new pumps are ‘water pressure tested” at the factory
This procedure permits a thorough inspection of entire drive
system and valving under simulated full load conditions.
The pump owner can do the same by making an adapter to
couple to the end of the discharge cone: e.g., the use of a
standard 2" pipe cap with a 3/8" drilled hole in the center,
screwed on to the end of hinged cone or reducer at the
pump.
Fill the hopper with water after making sure that all sand and
rock have been removed from manifold. Operate pump at
full throttle and the 3/8" diameter hole restriction will create
sufficient back pressure to make thorough inspection of all
moving parts.
THE EFFECTS OF HEAT AND EXCESSIVE
TIME ON CONCRETE:
Hot concrete, commonly referred to as a hot load, is
concrete that has been in the redi-mix truck in excess of 2
to 3 hours. On a hot day, this amount of time is even less.
A brief explanation of why heat and time affect concrete:
Concrete starts setting by drying up through a chemical
reaction. The catalyst to this reaction is heat. When
pumping a hot load, it is important to remember that
when you have to stop pumping for any reason, add
water to the concrete in the hopper and hand mix and
move concrete in the hose every 5 minutes. If the
shut down time becomes too long, wash out
immediately.
LS600 PUMP — PUMPING INFORMATION
If it is necessary to wait 1/2 hour or more for another load
of concrete, to prevent setting of the mix in the system, it
is advisable to consider the following factors (
A through D)
affecting the concrete:
A. How old is the concrete?
B. Is there an accelerator, calcium chloride, red label,
etc., in the concrete?
C. The temperature of the day, 80, 90, degrees?
D. How much system you have out and how stiff was
the mix you were pumping?
PREVENTING MIX SET-UP AFTER PUMP SHUTDOWN
When the pump is stopped for any reason during a pour;
e.g., moving hose, waiting for redi-mix truck, the following
suggestions are offered:
1. Leave the hopper full of concrete at the time of shut-
down. It is important not to let the redi-mix driver wash
too much water into the hopper, as this could cause
separation of the concrete in the hopper.
2. If the shutdown period exceeds 2 to 3 minutes, turn off
the engine so the vibration does not separate the mix
in the hopper which can cause a blockage in the
manifold when the pump is started.
3. If it is necessary to wait 10 minutes or more for another
load of concrete, it is wise to start the pump and pump
6 or 8 strokes every 5 minutes to prevent setting of the
mix in the system. If waiting time is excessive, it would
be wise to wash out the pump and hoses and start over
when the new truck arrives.
4. When pumping stiff mixes and there is waiting time
between redi-mix trucks, it is advisable to add some
water to the last hopper of material and “hand mix” to
ensure an easier start with the following load.
5. When the pumping job requires a stiffer mix, the
following method is suggested for starting: Take a water
hose with a nozzle on it and apply water with a fine spray
to the concrete as it comes down the redi-mix chute into
the pump hopper after the slurry procedure is com-
pleted and you are ready to start pumping.