7993 replies to this topic

[Victoria Watcher]

Yup

[Mike K.]

Victoria’s bridge builder has dropped plans to buy a US school.

A Chinese conglomerate will not buy a prestigious college, Westminster Choir College in Princeton, N.J., after opponents warned the sale would extend the threat of China's infiltration of American academia.

"China has now abandoned what would have been its first effort to control an American college, a trend that threatened U.S. academic and intellectual freedom," said Bruce Afran, the lawyer for a group of Westminster alumni opposing the sale. "American academic freedom is stronger today now that China has dropped this ill-fated attempt to control an American college, a trend that is now, hopefully, stopped for good."

- https://www.foxnews....ege-westminster

[Victoria Watcher]

any hydraulics experts on this board?

 

does this sound right?

 

https://www.timescol...rmal-1.23877721

 

He said the bridge is operating “well and as designed” and there has been no indication from its operations that something major is wrong.

 

“I’m not staring down the barrel of a huge, big maintenance burden or a huge, big replacement of gear or equipment. No one is talking about anything like that. It’s just about proving the system is working the right way and making sure we get the confidence back in the system,” he said.

 

The issue was discovered during the first maintenance routine since the bridge came into operation, Work said.

 

“Essentially, the indicator in the system said the pressure it’s taking to get the oil through has changed and it’s at its limits, so now’s the time to change the filters,” Work said.

 

That was done, but after the oil was inspected, a decision was made to further clean it, Work said, “We’re ensuring that the oil is clean by running it through an external set of filters and double polishing it, to make sure that it’s safe and sound,” he said.

 

“Because those systems run at such high pressures and they are so important to the overall health and the longevity of those components, we just said: ‘Let’s go to a slower-speed operation which has less pressure and let’s do that until we prove that the system is doing exactly what it needs to do and the filters are working exactly how they need to work,’ ” Work said.

 

Edited by Victoria Watcher, 06 July 2019 - 06:59 AM.

[Rob Randall]

If the system is properly maintained does that imply the works are overloaded and are generating particles from friction and wear?

https://www.sealinga...stem-get-dirty/

[spanky123]

I am not an expert but it sounds like a lot of BS to me. I guessing that reading between the lines what Fraser is saying is that when they did a fluid change and pulled the filters they found fillings. Being a new bridge and being the first maintenance then perhaps that is normal but it may also be a sign that the bridge mechanism are wearing much faster than anticipated.

[Mike K.]

That’s what it sounds like to me. And it required multiple filtering processes? That sounds like an attempt to ensure absolutely no particles remained to test the rate of particle contamination moving forward. The fact that there were particles discovered “by accident” suggests this was not a normal by-product, but who knows. The mechanism is unique, is it not?

[spanky123]

^ Or what they are doing is cleaning the fluid and filters and then running it again to see at what rate new fillings are being detected.

[Tom Braybrook]

If the system is properly maintained does that imply the works are overloaded and are generating particles from friction and wear?

https://www.sealinga...stem-get-dirty/

...yessir, one of the first things my daddy taught me was always clean your gun right after you use it ;-) ...

[phx]

That’s what it sounds like to me. And it required multiple filtering processes? That sounds like an attempt to ensure absolutely no particles remained to test the rate of particle contamination moving forward. The fact that there were particles discovered “by accident” suggests this was not a normal by-product, but who knows. The mechanism is unique, is it not?

 

The hydraulic pump and motor would be standard items, but I imagine they are still expensive.  It is a good thing the bridge is under warranty.  Oh, wait...

[Cassidy]

Sounds more like efforts at a layman explanation intended for the local newspaper (and likely hoping for no further questions from the public) rather than a detailed description of what's actually going on.

 

Increasing pressure requirements (over time) in a closed loop, high pressure pump system are always related to ever increasing friction somewhere in the wider system.

They (Mr. Works et al) seem to be implying (hoping?) that rather than ever increasing friction on the metal wear portions of the bridge, this issue is rather a diminishing efficiency in the actual hydraulic oil used in the closed loop, high pressure pump system used to operate the bridge.

 

Hydraulic fluids do wear out, so it's not impossible ... but it's also not a very likely explanation for the need for increased operating pressures in a less than one year old bridge, especially one with well known conceptual, mechanical, and fabrication design flaws.

[Victoria Watcher]

...yessir, one of the first things my daddy taught me was always clean your gun right after you use it ;-) ...

 

and wipe it down for fingerprints too.

[Victoria Watcher]

Sounds more like efforts at a layman explanation intended for the local newspaper (and likely hoping for no further questions from the public) rather than a detailed description of what's actually going on.

 

Increasing pressure requirements (over time) in a closed loop, high pressure pump system are always related to ever increasing friction somewhere in the wider system.

They (Mr. Works et al) seem to be implying (hoping?) that rather than ever increasing friction on the metal wear portions of the bridge, this issue is rather a diminishing efficiency in the actual hydraulic oil used in the closed loop, high pressure pump system used to operate the bridge.

 

Hydraulic fluids do wear out, so it's not impossible ... but it's also not a very likely explanation for the need for increased operating pressures in a less than one year old bridge, especially one with well known conceptual, mechanical, and fabrication design flaws.

 

in a perfectly - designed bridge the hydraulic dead-lift weight should be relatively small. it's not for example the pressure required to raise a home-lifting jack.  the whole thing is supposed to be relatively balanced on the fulcrum of the gears/rings and should just require some push to get it to move either way.  expansion (temperature) and debris and precipitation on the deck will cause the balance to go out slightly and require more push.  but it should not be that extreme.

Edited by Victoria Watcher, 07 July 2019 - 07:32 AM.

[Cassidy]

The "old" bridge was operated by a roughly 75 horsepower motor, and our "new" rolling bascule bridge is presumably even more efficient than that ... so you're absolutely correct in pointing out that we're actually talking about very little actual weight transfer as the bridge is raised or lowered.

 

The operating pressures are still likely quite high, as all closed-loop hydraulic systems tend to be, but presumably still somewhat in the range of a large excavator swinging a bucket full of rocks.

 

Of concern would likely be the extremely high dynamic loading that occurs whenever the bridge moves. It's likely this high dynamic loading that underlines officials concerns about these "new" higher hydraulic operating pressures they're seeing.

Essentially, moving something as large and heavy as the bridge (even though it's counterweighted) puts into play an incredibly high level of dynamic loading ... such that at any point in time if the hydraulic system failed in any way, the inherent potential in such a large and heavy structure would become incredibly dangerous to be around.

 

Presumably there are multiple safety systems designed to handle the dynamic load in a failure ... although the political fallout from such an occurrence makes this current "cautious operation" of the bridge more desirable ... even if it doesn't really address in detail (at least publicly) what's actually going on from a mechanical point of view.

[Gary H]

Just to be clear, as far as I can tell, the ONLY components of the new bridge that are hydraulic are the motors.  There are two direct-drive (to the pinions) hydraulic motors for each ring.  The ring support structure, called the "equalizer", is just a bunch of bearings and pivots.  There are no hydraulics in this mechanism.

 

Hydraulic motors were likely chosen over electric due to the operating environment.  Here's a comparison:

 

 

 

In this first pic you can clearly see the hydraulic hose going into the blue motor:

 

 

 

 

 

 

 

 

[Tom Braybrook]

^

 

thanks, nice explanation and pics

[Gary H]

Our new JSB cruise ship gets...  Deck chairs!

 

I guess we're staying with the blue theme here too.  But an event like the previous SKAM festival would require some/all of these chairs be unbolted so a stage could be set up, no?   

 

 

 

 

 

Edited by Gary H, 21 July 2019 - 10:08 PM.

[Nparker]

When it comes to the designs for the "surplus" JSB lands is the city just making things up as they go along?

[Hotel Mike]

I like those chairs. That's a good start.

[Nparker]

I like those chairs. That's a good start.

The implication being that this isn't the finished product. Is there any indication the CoV intends to introduce something here that enlivens the space 12 months of the year?

[DustMagnet]

I like those chairs. That's a good start.

Looks like Costco specials - I have some red and grey ones myself.

 

https://www.costco.c....100036005.html

But footstools and side tables, I did not know they also had.

 

EDIT: Maybe they'll add some of the aforementioned accessories?

Edited by DustMagnet, 22 July 2019 - 11:34 AM.