PDA

View Full Version : An Old EngineersTale or Have you heard the one about? (Sorry Guys it's a long one!)







Grizzly
21-10-2014, 06:46 PM
Hi Guys.
Please excuse the puns above, only as an Engineer fast approaching being put out to graze!
I rarely get the chance to justify some of the "Old School" comments that I have made in the past to Younger colleagues.
1 of my favourites has been " A Good Engineer that knows his plant, can tell if there is a problem when he walks into his plant room. Just by listening"!

I guarantee there are plenty reading this that know what I mean? Especially if they are site based!
Secondly there will be loads who even if they don't do Industrial, Supermarket Packs etc. that have seen what 2 pipes / surfaces rubbing together can do!

AC guys I bet have seen more than me!
So a few weeks ago I was on a site where I was to do what we call a "look and Log".
Basically the minimum attendance a customer can get away with but still comply with the relevant EN378 regs and have a Refcom 24/7 company provide back-up to their on-site Engineers / Electricians / Maintenance Staff.

So having booked in and reported to the relevant staff etc. I walk through the one plant room
With very, very old J&E Hall recips! Into the newer Annex with a Sabroe SMC116 Pac
Both are on Ammonia.
Listening to the Sabroe Recip load up and unload. I could hear something we have discussed a few times on the Forum Lately.
Basically I could hear the discharge gases pulsing / surging along the discharge pipes up towards the overhead Condenser and Receiver. This pulsing / surging was intermittently causing the relevant pipework to shake.

There was a resonance that was emanating from the system, but within this noise there was
the noise of something vibrating. I wasn't sure but my guess was it was something metallic?
As we are hopefully still taught? Not a Good Sound.
There where various things like cladding / Ally insulation which could be the culprit?
Following the shaking discharge line up through the roof on it's way to the condenser and Receiver ... Nothing!

Checking the returning 2" Steel liquid line however on the horizontal run that ran across the back of the pack. Halfway along I saw what I can only describe as a broken bracket which was once the bottom half of a 2" steel pipe saddle.
Because the centre line of this bracket was for some reason no longer in line with the Liquid line pipework. It had been snapped in half and was sat to the side of the 2" pipe.
Imagine the word LO, L being the bracket and O being the pipe. The toe of the L was against the pipe, both appeared to be rubbing together?
Because of the long unsupported pipe run I was able to gently push them apart. Instead of red oxide surfaces I saw shinny Metal. At this point I went and got one of the site shift Engineers.
He then went and fetched a cordless disc cutter and cutting off the remaining 1/4 bracket below the pipe at the point where it was welded to it's support stanchion.

The below Picture show what I saw!

11806


The Indent matches the toe of the bracket so perfectly that it's almost as if someone has got a cold chisel and driven it into the pipe!
You can even see the paint difference of the 2nd coat applied after the bracket!
Given that the system charge was (Unknown to me.) but would likely be something like 200 / 300kg Ammonia and the bulk was feeding this line from the receiver above.

I politely advised the customer that I would not be continuing with my service inspection. The damaged pipe would need a coded welder repair with agreement from the Insurance Surveyor.
This having been done the system needed topping up.

Myself and a colleague will be going back to isolate and purge the Liquid line and once the pipe has been welded. To add more ammonia and set the plant to work.

Long winded I know Guys, but a lesson all the same. Imagine no-one finding the damage, how long before a catastrophic Failure?

Not a bad days work Just for listening!
The Plant room that was maybe my 5th or 6th Visit in about 2 years.
So maybe you don't have to know the plant room so much after all?
Just don't ignore the noises
I like to pass these situations on, not for self glory. But someone reading this will apply the same one day and hopefully have a similar positive result. Because this stuff isn't in any text book. WE learn from talking to each other!!!!

Grizzly

monkey spanners
21-10-2014, 07:12 PM
Thanks for sharing!

The Viking
21-10-2014, 08:05 PM
Oh Grizzly,

A fellow proper engineer :)
How many times haven't I tried to get apprentices to understand that their best tools are called: Head, hands, eyes and ears.
Far too often nowadays you come across a nipper that think that the controls or the laptop will do the diagnostic for you. :(

(OK, in my current employment it might happen to be my job to teach engineers how to rely on controls and trouble shooting software but so what if I got double standards?)

:cool:

RANGER1
21-10-2014, 08:53 PM
Grizzly, thanks we all get satisfaction on finding these things & avoiding something more serious.
They are out there, but it seems less & less people who care & take pride in their work.

Most times it all in the details.

Rob White
21-10-2014, 11:06 PM
.

Fantastic find Griz.

You saved somebody a whole lot of money and grief.

Rob

.

PaulZ
22-10-2014, 02:35 AM
Hi Grizzly
Very good post I hope some of the younger guys on this forum take heed. I am like Viking when it comes to telling apprentices to use their senses. I often tell our guys if you go to a breakdown take a bit of time to listen to the plant as well using the other senses not to just go to the fault page on the PLC / Computer.
I think most of the older guys will agree that we had to use our senses when we first started as we didn't have all the electronic gear 30 years ago.
Paul

cadwaladr
22-10-2014, 03:51 AM
Totally agree,listening looking for future problems is a sixth sense ,I had a customer who had a major ammonia leak years ago I only did the transport work at this site at the time,the customer stored heated water via the plant 4000 gallons the fire brigade hosed down,but the staff went down with stomach problems and nobody could understand why? until I informed them that the stored water was full of ammonia schoolboy error ,needless to say much rinsing took place.

Gibbo
22-10-2014, 08:27 AM
Well done mate but regarding the bit about "fast approaching being put out to graze" surely not a young un of your calibre. :D

redroge
22-10-2014, 09:37 AM
In the old days it was feel the pipes one hot one cold one warm it was a good place to start.

Rob White
22-10-2014, 11:30 AM
In the old days it was feel the pipes one hot one cold one warm it was a good place to start.

I still do that now and if you look at the finger tips of
a lot of the older fridge engineers, they have next to
no fingerprints. We have left our fingerprints either
melted or frozen to so many pipes over the years
that we now have next to none left.

A perfect crime waiting to happen, no unfortunately
because we leave that much skin behind they would
find us by our DNA.

:D

Rob

.

hookster
22-10-2014, 07:36 PM
There is some life left in the Old Dogs! :cool:

Ps did you get a bottle of their finest for your efforts?

Grizzly
22-10-2014, 07:41 PM
There is some life left in the Old Dogs! :cool:

Ps did you get a bottle of their finest for your efforts?
Hi hookster.
Not yet, but am working on it!
The plant is being shut down come next Autumn, allegedly!
We shall see at least the customer is happy!
You Good?
Grizzly