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SLF 2250/4000
Hydromatic Stinger
Technical Description
Computing maximum lift
Lift is measured from the surface of the
static source to the centerline of the
pump. The height of possible lift is not
affected by the angle of the intake hose,
but depends on the vacuum that the
pump (priming pump) can produce and
the atmospheric pressure.
Theoretically, at sea level a pump can
lift water 10 m (33.8 feet). A perfect
vacuum is impossible with a fire pump
and there will be loss due to friction, so
the maximum lift is nearer to 6 - 7.6 m
(20 to 25 feet).
The height that water can be lifted
decreases with altitude by about 0.3 m
(1 foot) for each 300 m (1000 feet) of
elevation.
The weather also affects drafting, but
to a smaller degree.
Priming system KAP 600
Since a centrifugal pump is not a self suction pump, a priming pump
system is installed, which removes air from the pump allowing the
subsequent vacuum to fill the pump with water. The piston priming
pump is mounted with a pivot on the suction cover. It is driven by
two V-belts and a belt tightening device. The priming pump has to
be engaged only for the priming procedure.
The housing and the pistons are made of corrosion resistant light
alloy. The cylinder liners are made of stainless steel.
Two pistons, provided with sealing and guide rings, are fitted
together in a single unit. This double piston is driven by a sliding
pad, which is driven by an eccentric shaft.
The moving parts are oil bath lubricated and suction and pressure
valves are concentrically arranged in the cylinder heads (valve
covers).
priming pump
Working principle:
Upon engaging the priming pump (**) the ball valve mounted in
the suction line will be opened. At the same time, the V-belts for
driving the piston priming pump are tightened by a pneumatic
cylinder. The priming pump now has approximately twice the
speed of the centrifugal pump.
The rotating eccentric moves the piston to and fro. By the move-
ments of the piston the vacuum (priming stroke) and simultaneous
pressure (pressure stroke) are produced. The diaphragm-design
valves are concentrically placed in the suction covers. The pump
system is evacuated and water is forced into the water pump.
As soon as water is discharged from the piston priming pump the
priming procedure is completed (**). The suction valve closes and
the V-belts are released from tension via a pneumatic cylinder.
When the water column breaks, this procedure is to be repeated.
** As an option the priming pump is controlled automatically.