VI. TESTING A STEAM TURBINE[4]
[4] Contributed to Power by Thomas Franklin.
Special Auxiliary Plant for Consumption Test
There are one or two points of importance in the conduct of a test on a turbine and these will be briefly touched upon. Fig. [70] illustrates the general arrangement of the special auxiliary plant necessary for carrying through a consumption test, when the turbine exhaust passes through a surface condenser. The condensed steam, after leaving the condenser, passes along the pipe A to the pump, and is then forced along the pipe B (leading under ordinary circumstances to the hot-well), through the main water valve C directly to the measuring tanks. To enter these the water has to pass through the valves D and E, while the valves F and G are for quickly emptying the tanks when necessary, being of a larger bore than the inlet valves. The inlet pipes H I are placed directly above the outlet valves, and thus, when required, before any measurements are taken, the water can flow directly through the outlet valves, the pipes terminating only a short distance above them, away to an auxiliary tank or directly to the hot-well. Levers K and L fulcrumed at J and J are connected to the valve spindles by auxiliary levers. The valve arrangement is such that by pulling down the lever K the inlet valve D is opened and the inlet valve E is closed. Again, by pulling down the lever L the outlet valve F is closed, while the outlet valve G is also simultaneously closed.
FIG. 70
During a consumption test the valves are operated in the following manner: The lever K is pulled down, which opens the inlet valve to the first tank and closes that to the second. The bottom lever L, however, is lifted, which for the time being opens the outlet valve F, and incidentally opens the valve G; the latter valve can; however, for the moment be neglected. When the turbine is started, and the condensed steam begins to accumulate in the condenser, the water is pumped along the pipes and, both the inlet and outlet valves on the first tank being open, passes through, without any being deposited in the tank, to the drain. This may be continued until all conditions are right for a consumption test and, the time being carefully noted, lever L is quickly pulled down and the valves F and G closed. The first tank now gradually fills, and after a definite period, say fifteen minutes, the lever K is pushed up, thus diverting the flow into the second tank. While the latter is filling, the water in the first tank is measured, and the tank emptied by a large sluice valve, not shown.