Disappointment at the hydro-electric plant which has been shut down again for an extended period. Last year we had a problem with the bottom bearing which blew itself to bits in a way which suggested a design issue; but on the grounds that it could have just been a faulty bearing, we agreed to have the bearing replaced and see what happened. (Below: what remained of the bearing in 2012).
Well, ten months after the replacement was put in, the problem has returned. This time, upon inspection it was found that two of the bolts holding the bottom beam upon which the bearing is mounted had sheered off - that's quite a force needed to achieve that, and certainly enough to have caused the damage to the bearing. What could be causing this?
Our system has the bottom bearing held by a very strong, steel beam (above). We always had our suspicions about this beam as a design feature - because it is very close to the flights of the screw itself and consequently causes an obstruction to water trying to escape. This cannot be efficient and as the water falls out of the flight onto the beam, shock waves pass back up through the shaft - these can be felt keenly in the machine room above.
Have a look below to see the beam causing some serious disruption to exit-flow.
A re-design is required, and so in the coming weeks we shall see a new mounting for the bottom bearing.
The good news is that it has happened during the first dry spell for months, making the work much easier, and the loss of generation less significant.
No comments:
Post a Comment