Operation
All
S
P Rock Valve Model
s
Startup 250:Users:Danny:Desktop:Operation manuals:line
pumps:All SP Rock Valve models:Frame files:operation.fm
Operation Manual -
87
If any of the listed items made it into your hopper, they
would probably cause a blockage, which is always
dangerous. Worse would be if you fell into the hopper.
In any case,
it is
da
n
g
ero
u
s to o
p
er
a
te witho
u
t the
g
r
a
te o
v
er the ho
pp
er.
Blockage
s
If you have a blockage in your pipeline that you cannot
remove by the backward / forward rocking motion
described on page 83, you will have to disassemble the
pipeline to find it. Before you disassemble the pipeline,
you MUST relieve the pressure by pumping in reverse
for several strokes.
Yo
u
m
u
st not for
g
et this ste
p
!
•
When you go to the pipeline to find the
blockage, take your hammer with you. Wear
ALL of your personal protective devices for
this procedure. 99.9% of the time, you will find
the blockage in a reducer, hose or elbow. The
act of reversing the pump will make the
pipeline sound differently, when tapped with a
hammer, than if it were pressurized. ‘Tapped’
is a key word here. You can damage the pipe by
striking it hard. You should be able to hear the
difference. An empty pipe has a definite
reverberating “tong” sound. A relieved pipe
will have a meaty “thak” sound, and a
pressurized pipe will have a thin “tik” sound
because the forces on the steel will not allow it
to vibrate. Once you have located the
blockage, CAREFULLY remove the clamp(s)
from the blocked piece(s). If you are not
wearing a full face shield, turn away from the
clamp as you pull the handle. Providing you
have relieved pressure by stroking in reverse,
you should be OK, but sometimes a blockage
will store pressure because there is another
blockage up or down stream. It’s better to be
safe than sorry. Once the clamps are removed,
the danger is past. Displace the blocked piece
enough that you can push a piece of rebar or
other long poking device into it. If the
blockage is in a hose, it will help to hit the
outside of the hose with the hammer. Again, do
not damage the hose by hitting it so hard that
the steel braids inside get permanently
disfigured.
•
Once the blockage is removed, clean up the
clamp, gasket, and pipe end with a rag or, in a
pinch, wipe the concrete off with your hands.
Reassemble the pieces, and pin the clamp(s) if
they will hang overhead. Return to the pump
and start pumping in forward again, slowly at
first, until you are sure that there are no more
blockages. If another blockage is encountered,
remember to relieve the pressure again by
pumping in reverse for several strokes, before
finding the remaining blockages.
•
Do not use compressed air to remove a
blockage. Your concrete pump has at least 6
times more pressure available than an air
compressor. If the pump won’t push the plug,
air certainly won’t. In addition, air that is
compressed builds a reservoir of pressure that
will continue to be dangerous even when the
compressor is shut off.
Clean-out
It is an unfortunate truth, in many cases, that you will
have to wait for the “balance load” of concrete. This is
usually 1 or 2 yards that weren’t ordered by the
contractor until the last minute. It usually happens late
in the day, so typically 4 of the 5 ready mix drivers that
you were seeing all day have gone home, and the same
man that brought the next to the last load will have to
go and get the balance load. This gives you time to get
ready for clean-out and to stow pipeline, clamps, etc.,
but it has the disadvantage that the concrete in your
machine will be old by the time he returns. This is the
most dangerous time for setting in the machine. Be
aware of it, and take any steps necessary to keep the
concrete alive. Clean out if you have to, but if the
balance load is very small, refilling the hopper,
material cylinders and pipeline may use up the entire
balance load without ever delivering concrete to the
form. In that case, they would have to order another
balance load, and no one is going to be happy about it.
When the balance load arrives, it is usually fresh
concrete. That means that if you pump at least 1/2 yard,
your machine will be filled with fresh concrete for
clean-out, which is to your advantage. The worst thing
that can happen is: On a hot day, the balance load is
only 1 wheel barrow full. You will not be able to get
fresh concrete all the way through the pipe when you
pump the balance load, so the concrete that is in the
end of the pipe for cleaning is as old as the next to the
last load. BE CAREFUL! With old concrete it is
imperative that the pipe is cleaned immediately upon
finishing the pour.
Check Your Water Supply! You Will Need Water For
Clean-out.
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