Operating experience and reliability assessment of elements of pumping stations

Conclusions

• 1. An analysis of the causes of failures of PUs from the standpoint of reliability theory enbles design and operating organization to increase the probability of no-failure operation by revealing and reconstructing limiting elements.

• 2. An evaluation of the intensity of the thermal effect of solar radiation on the concrete of water-supply structures of PSs with consideration of seasonal and daily maxima of the effect of insolation showed that in July–August consideration of insolation adds to the daily mean ambient temperatures up to 10–15°C. This value must be taken into account when predicting cavitation phenomena in pumps.

• 3. Daily variations of the intensity of insolation affect the stress-strain state of the structures, increasing during the growing season the compressive stresses on surfaces exposed to the sun, which also must be taken into account when designing and operating hydraulic structures of PSs. The absolute maxima of the temperature of the pumped water and cavitation phenomena occur in the evening. The simplest measure reducing the variation of the intensity of insolation is to paint white the exposed surfaces of the intake of the PS, thereby reducing K_s in formula (4).

• 4. The new layouts of the structures and devices improve the hydraulic conditions of the supply of water to the PUs, facilitate the removal of sediments and driftwood, and reduce the production costs of the water being pumped.