Schwing 30100750, Руководство по эксплуатации

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Appendix
Operation Manual - All S P Rock Valve Model s 140 revD a te
material cylinders. Usually, the unit is
designed so maximum output can be achieved
only at less than maximum pressure.
3. M a xim u m Press u re (abbreviated as max
P) is determined by the size of the differential
and material cylinders and the setting of the
main relief valve. To be sure that the unit will
handle the job be careful to notice max P and
max Q. Here is an example of why that is
important. You only need 20 yards/hour, but
you calculate that you will need 1900 PSI
pressure. The TK of this job is 2000. The pump
has a TK of 2775, so there is enough power
available,
BUT ... the maximum pressure
available from the pump is only 1570 PSI. This
pump wouldn’t do the job.
b. Follow the chart in a straight line from
required output into the upp er ri g ht q uad r a nt
until you come to the size of the pipeline that
you will use. A good rule of thumb for sizing
pipeline is to use the largest diameter pipeline
that you can. It takes less force to move
concrete through a 6" pipeline than, for
example, a 4" pipeline. When pressure is
exerted on concrete in a pipeline, a paste of
water and cement fines coats the inside of the
pipeline and forms a slippery layer on which
the bulk of the concrete slides. While it is true
that a 6" pipeline has more surface area to coat
than a 4" pipeline (49% more), the volume of
concrete that can move on the layer is
increased by 125% which results in lower
velocity of the concrete (in feet per second),
lower friction, and therefore lower pressure. A
pump that may not be capable of completing a
difficult job through 4" or 5" pipe may very
well be able to do it through 6" pipe.
NOTE!
Ex p erience h a s t aug ht u s th a t 5" is the
o p tim u m p i p eline size for len g thy v ertic a l
r u ns s u ch a s those fo u n d on a hi g h rise
b u il d in g . It is l a r g e eno ug h for most
agg re ga te, b u t sm a ll eno ug h th a t yo u
minimize b a ckers when the concrete va l v e
cycles. Yo u m u st a lso consi d er the men a t
the p oint of p l a cement. There a re v ery few,
if a ny, hose men th a t c a n mo v e 6" hose on a
sl a b a ll da y. There is no p ro v ision in the
nomo g r ap h for mixin g p i p eline sizes. F or
ex a m p le, if yo u will be re du cin g from 5" to
4" p i p e yo u sho u l d c a lc u l a te the ch a rt a s if
yo u were u sin g 4" p i p e for the entire
d ist a nce. This will not be com p letely
a cc u r a te, b u t yo u will be s a fe in yo u r
p ress u re c a lc u l a tion. In o u r ex a m p le, we
will u se 5" p i p eline ( F i gu re 68).
Figure 68
Upper right quadrant - Pipeline diameter
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