General information – Multiquip LS-300P User Manual

Page 21

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MAYCO LS300P CONCRETE PUMP • OPERATION MANUAL — REV. #0 (06/09/14) — PAGE 21

GENERAL INFORMATION

The following is a brief explanation of how the concrete

cylinders, hydraulic cylinders, shuttle tube, valves and

hopper work in sequence to pump concrete.
The hydraulic pressure is generated by a variable volume,

pressure compensated, axial piston pump that is driven by

a diesel engine. The rod sides of the drive cylinders are

hydraulically connected together creating a “slave circuit,”

which allows hydraulic oil to transfer from one piston to

the other.
The two part cycling sequence is initiated by an electrical

signal generated by two proximity switches activated by

the drive cylinder. The proximity switches are normally

open, magnetically sensing the movement of the main

drive cylinder. As the drive cylinder piston head passes the

proximity switch, an electrical signal is sent to the solenoid

operated pilot valve which in turn directs pilot oil to the four

valves controlling the drive cylinder and the shuttle cylinder.

Figure 3. Pumping Cycle 1

TO TANK

HIGH PRESSURE

OIL FROM PUMP

PROXIMITY

SWITCH

HYDRAULIC
CYLINDERS

PISTON

CUP

CONCRETE
CYLINDERS

SHUTTLE TUBE

SLAVE

OIL

SHUTTLE TUBE MOTION

Figure 4. Pumping Cycle 2

In the first cycle (Figure 3), hydraulic pressure is applied

to cylinder (

B), causing the hydraulic piston, which is

connected to the concrete piston and piston cup, to

discharge concrete into the delivery line.
As one cylinder is discharging concrete, the hydraulic

oil from the rod side (

B) of the drive cylinders is being

transferred through the slave circuit causing the opposite

cylinder (

A) to move back on the suction stroke, filling the

cylinder with concrete.
The shuttle tube is sequenced to pivot to each concrete

cylinder as the drive cylinders stroke to push concrete. As

the second cycling sequence begins (Figure 4), the shuttle

tube pivots to the opposite cylinder (

A).

The hydraulic piston passes under the proximity switch

and sends pressure to the piston, causing it to stroke

and discharge concrete into the delivery line. Hydraulic

oil is transferred through the slave circuit to cylinder (

B),

causing it to start a suction stroke, refilling it with concrete.

The pumping sequence then repeats for the duration of

the operation.