Schwing SPB 28, Руководство по эксплуатации

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71
Operation
SPB Operation Manual
If workers are positioned in high or precarious places,
warn them to expect a loud sound as the air escapes
the pipeline. (Warn them even if they are well away from
the discharge.) That way, you can prevent the worker
from falling as a result of being startled by the noise.
Warn everyone to stay away from the discharge when
initially priming the delivery system, when restarting
for any reason, or whenever air has been introduced
into the line, until concrete runs steadily and there is
no movement of the delivery system. Personnel should
stay back from the discharge a reasonable and prudent
distance.
Always keep an eye on the point of discharge or your
spotter, so you can respond to dangerous situations
quickly.
The boom movement is proportional. This means that
the boom adjusts its speed in response to the move-
ment of the joysticks. The farther the joystick is moved,
the faster the boom moves.
If you are pumping out of the boom into a slickline, fre-
quently check on the hose that connects the two. Never
allow the boom to go down so low that the hose kinks,
nor up so high that the weight of the first pipe is hanging
from the boom, and never allow the boom to rest on the
deck.
Boom bounce
All booms bounce. A steady boom is one that simply
doesn’t multiply its natural flex forces but, rather, works
against them. Every boom model has a “natural reso-
nant frequency” that determines how it will perform un-
der certain pumping conditions. Engineers can deter-
mine that a boom has an unsuitable resonant frequency
for a certain application after the fact, but predicting it
in the design stage is nearly impossible. Severe boom
bounce is caused by taking the natural stiffening and
relaxing motion of the boom during the stroking of the
pump and multiplying it. For example, when a stroke is
finished and the concrete valve is switching, the boom
relaxes with a downward droop. The worst case scenar-
io would be to re-pressurize the concrete as it reaches
the limit of the droop and begins to “bounce” upwards.
When that happens, the natural spring of the boom and
the stiffening action of pressurizing the concrete will
work together to multiply the upward force.
To avoid these problems, some precautions must be
taken during setup:
•The boom must be placed in a favorable position as
shown in (Figure 39). Example “B” has more boom
bounce than example “A” because of vertical support
at the pivots. This vertical support is the same reason
that houses have pitched roofs and indoor stadiums
have domes instead of flat roofs.
•If the boom still bounces more than you would con-
sider acceptable, the last option is to change the
speed of the concrete flow through the use of the
stroke limiter.
Distance “X”
Distance “X”
A
B
Figure 39
Two boom positions with the same end hose location.
Example “B” multiplies boom bounce.
Clean system quickly
Wash pipes, clamps, and gaskets with water as the day
progresses and the crew removes pipe sections from
the end of the slickline (Figure 40). If you don’t wash
them until the pour is finished, you will not be able to
get the hardened concrete out of them. If possible, any
system that is removed during the pour should be flown
to the ground and washed as soon as possible.