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PAGE 54 — MAYCO ST-45HRM CE PUMP — OPERATION & PARTS MANUAL — REV. #0 (02/23/04)
NOTE
Important notice! During freezing
temperatures, completely drain the
Lubrication Box and cover the hopper
after each use. Frozen liquid will
restrict the piston travel and cause
damage to the pump.
CLEANING THE LUBRICATION BOX
1. Remove the top cover and the drain plug (Figure 53) located
at the bottom of the box and fully drain the inside of the box.
2. Once the box is drained, start the engine and stroke the
cylinder (
keep hands out of box
) ten to fifteen times.
3. While stroking, spray water inside of the box to thoroughly
clean out all contamination (Figure 53).
4. When the box is clean replace drain plug, add new
lubrication and install the top cover.
1. The lubrication level should be checked everyday prior to
pumping and maintained at a height of 12.7 cm (5 inches)
or about half the concrete cylinder height. We reccomend a
using a soluble type oil (water & oil mixture)
CYLINDER LUBRICATION BOX
Figure 53. Cleaning the Lubrication Box
ST-45HRM CE CONCRETE PUMP— MAINTENANCE (PUMP)
ST45 ACCUMULATOR CIRCUIT
Figure 54. Accumulator
CHECKING ACCUMULATOR BLADDER PRESSURE
The normal accumulator charge pressure should be
approximately 7.58 mPa (1,100 psi). To check the accumulator
pressure:
1. Start the engine and stroke the pump. The
accumulator
pressure gauge
(Figure 29) should read 12.07 mPa (1,750
psi).
2. To determine the actual accumulator PSI, stop the engine
and observe the pressure gauge. As the PSI reading slowly
decreases, it will reach a point where there will be a sudden
drop in the PSI. The PSI reading should be taken just prior to
this sudden drop. If you do not read 1100 PSI, the accumulator
may require charging or bladder replacement.
When the pump cycles, a part of the stored oil is released to the
shuttle cylinder. This pressure release assures the shuttle tube
has enough force to shear the cylinder of concrete passing from
the concrete cylinder to the concrete delivery line during the
cycle phase.
CAUTION
Before checking lubrication level, stop the
engine and remove the ignition key.
2. As the rubber piston cups naturally wear, fine cement
particles will accumulate in the box. Once the concrete paste
reaches a height of about ½ inch from the bottom of the box,
drain and clean the lubrication box.
Improper accumulator charging can result in an explosion
causing serious injury or death! NEVER use oxygen or
compressed air to charge the accumulator! Only qualified
personal should perform this procedure. Use only
dry
nitrogen
to charge the accumulator. Contact your Mayco
service department or your local Hydac representative for
proper charging procedure.
DANGER
The accumulator circuit has two functions in the hydraulic system.
■
The accumulator circuit furnishes the hydraulic pressure
to cycle the shuttle tube.
■
The accumulator circuit also furnishes the pilot pressure
necessary to activate the hydraulic system.
The accumulator circuit is equipped with
a bladder type accumulator (Figure 54)
charged with 7.58 mPa (1,100 psi) of dry
nitrogen. The accumulator stores 3.78 liters
(1 gallon) of hydraulic oil, which is, under
12.07 mPa (1,750 psi) of pressure.