When using a horizontal shaft version of an engine of this type, some additional components and details are needed to implement the design. This arrangement is an interesting variation and it can be in the form shown in Figure 07.05.15. Here, the conical wall KW (shown shaded in grey), turbine T and the turbine inlet TE are similar to those already discussed. At the outlet A however, water now falls downwards (as indicated by the blue dots) through the air-filled area (shaded in light yellow) into the reservoir. As in the previous example, at the outlet there is a safety-valve B (shown in yellow) which is installed to control the flow.
Water flows into the backflow tank R (shaded light blue). From there, it is guided towards inlet E via pump P (shown shaded green) and the snail-conduit C. This inlet-conduit is arranged diagonally, so that water enters the space between the conical housing wall and the turbine cone at the angle required for the operation of the turbine.
The pump is installed fairly low down in the water tank as it is only used when starting the turbine from standstill. Once the turbine is running, the turbine creates sufficient suction to maintain the water flow without the need for the application of any external power. The water pump just turns idly when the turbine is running, rotated by the water flow caused by the suction created by the rotation of water inside the conical turbine section. It is actually possible to boost the rotational speed of the turbine by powering the pump and thus boosting the mass flow through the turbine.
In principle, any pump could be used in this position. In this example, the schematic shows a 'slide-pump' P with its eccentric shaft and radial-moving pump blades PS (shown in dark green). The advantage of this kind of pump is that it has a precisely known volume contained within it's chambers and that exact volume is transported during each revolution. Hence, the pumped volume is exactly proportional to the pump revolutions.
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