Alamarin Jet AJ 340, Руководство по эксплуатации и обслуживанию

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The jet propulsion unit
Operation and maintenance manual
KHO/340/EN/1.0.0. 3
2. The jet propulsion unit
The Alamarin-Jet water jet propulsion unit (jet) is a single stage mixed flow
pump, which produces a high volume flow rate and thrust with high efficiency.
The operation of the unit is based on increasing the water flow rate in the
nozzle. The change in the flow rate creates a reactive force in the direction of
the flow, which thrusts the boat forward. By changing the direction of the jet
flow, the boat can be steered in the desired direction.
The jet gets its propulsion power from a petrol or diesel engine. The most
common way to transmit the power is through a gearbox, but a direct
drive installation is also possible and functional. The greatest benefits of
a gearbox are a real neutral gear and an intake duct backflush. In bobtail
installation, it is commendable to use a flywheel adapter provided by the
engine manufacturer. This will protect the engine from mechanical damage
and corrosion, for example.
2.1. Structure
The jet consists of four main parts (figure 1). These are specified in the table 2.
Figure 1. Main parts of the jet
Table 2. Purpose of the main parts of the jet
Part Purpose
Intake duct (A) Leads the water from outside the boat to the intake side of
the impeller. Keeps the loss of power as small as possible
and distributes velocity evenly.
Impeller (B) Increases the water's flow rate. The impeller is rotated
by the driving motor. The nozzle converts the pressure
energy produced by the impeller into motion energy.
Steering device
(C)
Changes the direction of the jet flow coming out of the
nozzle, which creates the force needed for turning.