Posted on 02/07/2014 10:58:37 PM PST by steve86
The Highway 99 tunnel machine could be sidelined for several more weeks, to fix damaged seals that lubricate and protect the drive system that spins the giant cutter.
The revelation comes two months after the drill failed to grind ahead and operators shut it down. The machine known as Bertha tweeted in December that she was doing fine, just facing an obstruction. An 11-day inspection in January found no big obstacles, turning engineers’ attention inward.
Officials on Friday announced the seal assembly is damaged, and that probably contributed to heat spikes within the main bearing Dec. 7 and during a restart attempt Jan. 28-29.
(Excerpt) Read more at seattletimes.com ...
That article reads that a lab. seal is better able to hold lubricant fluid in better than traditional seals but not that it lubricates.
Correct. The should replace these seals with sea lions or maybe with a walrus or two. coo coo cah cho.
“...there is a small chance I am wrong.”
I thought I was wrong once but, I was mistaken ;)
I might not always be right but I’m never wrong. ;)
There was no mention of the rock hardness nor the cutter hardness.
When the hardness of the latter is near or less than than the former heat will be transmitted from the face back through the shaft
>> Replacement seal: $5 Million <<
It appears from the article that the whole bearing unit (which they do not think will need to be replaced) is $5 million, not just the seal(s).
Seals are probably on 3 or 4 million. heh
When this project was approved by the State of Washington, it was contingent on the City of Seattle covering any expenses above and beyond the original price tag.
Hard for me to feel sorry for these fools who always vote for the (D)ummies.
Who actually “OWNS” this cutting machine? The state or a contractor? If it’s the state, I’d really like to see an investigation and statement of charges against the operator or supervisor who let this happen. Someone is negligent to the tune of $5M and the cost should not just be passed to the taxpayers.
This is primarily a soil boring machine; some small boulders and rocks which get ground up (hopefully). But the soil down there is quite compressed and hard; I have heard that if you used a pick on it, it would seem like concrete. No problem for the cutters, though.
I have seen Mexicans do jobs like that. Would take me 5-10 years.
They thought the steel well casing they went through may have caused problems. But looking at the timeline, WSDOT was concerned by the elevated temperatures from the beginning. So perhaps a design flaw, or some problem at the very start. (Hey - did any body put the lubricant in those things?)
Last year in Seattle a 10-year old highrise had to be demolished because someone didn’t put a dab of silicone on the ends of the stress cables in the concrete and they started rusting.
I agree that it is not terribly clear but it is considered one of advantages of this design.
Reducing friction is what lubrication is all about.
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