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Chapter 11 to 13

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11. Handling of battery

(1) Unless battery discharged, it can be cause of trouble. Even if slightly discharged, charge the battery on the same day (or if possible, the next day). Keep charging until many bubbles appear in the electrolytic liquid after voltage and specific gravity reaching their highest values.
(2) When battery electrolyte level goes down to specified lowest level, add distilled water up to specified highest liquid level. In this case, always use distilled water; never add well water, river water or dilute sulfuric acid.
(3) Always keep outside of battery clean. In case sulfuric acid adheres on it, wipe it off and dry.
(4) Battery discharge by itself (about 30% in 1 month) when not in use. Even if charged once a month, battery may not be fully charged, and recovering capacity gradually drops. Therefore, it is necessary to shorten charging intervals. Finally, you may have to charge it once a week or once in five days with aging. It is time to replace battery with a new one.
(5) To know discharging condition of battery, measure specific gravity of liquid and terminal voltage, with reference to following table.


12. Features of fire pump

Fire pump requires high discharge pressure and compactness. For this reason, a turbine pump with guide blades is used.


Features of turbine pump are as follows:

(a) Less vibration during operation.
(b) Even dirty water will not cause trouble.
(c) Uniform water discharge.
(d) Running may continue without trouble even when water discharge is closed.
(e) High speed rotation is allowed.
(f) Performance will not deteriorate as no friction part is employed.

Fire truck requires a higher discharge pressure than portable one. For this purpose, two-stage turbine pumps or three-stage turbine pumps are employed.


13. Performance of pump


HQ Curve shows pumps performance. Discharge pressure of pump will rise when discharge volume is reduced, while discharge pressure will drop when discharge volume is increased. Also, the Curve shows that the greater suction height, the lower discharge pressure and volume.

You can also see, from this Curve, limits of discharge volume and pressure according to nozzle diameter used.



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【参】BSI-EN:フッターナビ