Red Jacket LPG Premier, Руководство по установке, Страница: 7 / 40

Introduction Basic Principle of the Red Jacket Submersible LPG Pump
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Basic Principle of the Red Jacket Submersible LPG Pump
Red Jacket submersible LPG pumps are multi-stage centrifugal pumps. The advantage of the multi-stage
technology is maximum performance by a minimum of energy, respectively 2.25 kW (3 hp) for the Premier pump,
2.25 kW (3 hp) for the Mid-Flow and 3.75 kW (5 hp) for the Hi-Flow pump. During operation, the pressure
increases with approximately 50 kPa (7.25 psi) per stage up to the maximum design pressure of the pump
respectively 1000 kPa (145 psi) for Premier, 880 kPa (127 psi) for Mid-Flow and 1220 kPa (180 psi) for Hi-Flow.
LPG is a mixture of gasses, primarily propane and butane which are vapors at atmospheric pressure. This means
as long as the mixture is under sufficient pressure the mixture remains liquid.
Every stage consists of three parts; a. the diffuser, b. the diffuser plate and c. the impeller. The impellers are
working on the floating principal. This means that during operation the impellers are floating in the liquid. Between
the impeller and the diffuser and between the impeller and the diffuser plate there is a liquid film. This floating
principle avoids any unnecessarily resistance in the pump. As long as all the impellers are floating in the liquid, the
pump runs on maximum capacity with a minimum of energy. All respectively, 17, 21 or 24 diffusers are interlocked
and are enclosed in a stainless steel shell. There is not a requirement for initial bearing running-in period for the
Red Jacket submersible LPG pumps.
For all types of Red Jacket submersible LPG pumps, the minimum differential pressure can never be allowed to go
below 400 kPa (58 psi). This minimum required differential pressure of 400 kPa (58 psi) is to guarantee that
during operation all respectively 17, 21or 24 stages are submerged in the LPG liquid.
Another basic rule for a centrifugal pump is that there must be sufficient liquid available by the inlet of the pump.
The pump can only build differential pressure when the first stage of the pump is completely submerged in the
liquid. This NPSH (Net Positive Suction Head) is for all types Red Jacket submersible LPG pumps 127 mm (5.0
inches) above pump inlet opening.
The motors provided in these submersible pump-motor units are flameproof type 1180
e
II 2 G Ex db IIA Gb
with the certificates DEMKO 13 ATEX 9483031U and IECEx UL 13.0034U. They are designed to permit the LPG
to flow through and around the motor and contain an internal bleed (by-pass).
The pumped liquid flows from the impellers between the motor shell and the stator, upward to the column pipe. A
calculated part of the liquid passes through the motor flame barriers (breathers), motor bearings for cooling and
lubrication. This amount of liquid passes through a self-adjusting bypass back into the pumped liquid. A calculated
part of the pumped liquid passes through the internal by-pass to the manifold or storage tank to provide cooling for
the pump/motor assembly.