Boiler Safety v/v

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46Tall
Bilge Dweller
Posts: 9
Joined: Fri Oct 14, 2011 8:32 pm

Boiler Safety v/v

Postby 46Tall » Fri Jan 01, 2016 5:48 pm

Having a bit of discrepency; can anyone out there shed some light on the proper way to float the safety valves of a low pressure boiler??

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JK
Enduring Contributor
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Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: Boiler Safety v/v

Postby JK » Sat Jan 02, 2016 3:18 am

screw the safeties down. Override the automatic flame shutoff. Flash boiler to blowoff pressure which is operating pressure plus 25%. Screw out safety until it blows off at required pressure. You have someone watching the boiler front and pressures. Monitor blowdown length and pressure drop before safety seats. Gag that safety and repeat with second safety. Take gag off and flash boiler to test operation and pressure drop with safeties reseating. Check uptake to make sure they reseat and aren't leaking by
Return boiler to normal operating. Install wire seals on safeties, replace easing gear.
In a nutshell. Feel free to correct or add, it's been a while lol. I wonder how many times I was sent to the top of the scotch marine boilers to find the leaking safety. 3 boilers, 6 safeties, it was always the last one you checked . I think the 2nd saved them for hungover engineers.

I'm not dealing with the ships very much these days, onto the more rarified air of HQ (gasbags). How many ships are actually setting safeties anymore, other then at sea? Are they being tested ashore and certified for ISM?

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Merlyn
Fleet Engineer
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Joined: Wed Dec 25, 2013 7:19 am
Currently located: South Coast UK

Re: Boiler Safety v/v

Postby Merlyn » Sat Jan 02, 2016 6:49 am

Reckon JK just about recalled it all but what about the person in the stoke hold shouting "on the blood " when the needle touched the red. Or at least if you were the person screwing down the safety valve you had a backup down below in case he nodded off. That's what some of the wags on needle watch used to say, had a late night last night, hope for your sake I don't nod off till the 25 per cent overload kicks in ,confidence inspiring workmates or what, bit of a hotter so job to boot I recall.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.

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JK
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Joined: Tue Sep 04, 2007 2:29 am
Currently located: East Coast, Canada

Re: Boiler Safety v/v

Postby JK » Sat Jan 02, 2016 3:01 pm

We had the fireman firing the boiler, a man standing by yelling the pressures out, someone on top repeating to the engineer setting the safeties. That was 220 Psi. Then the superheats..we e ither set them first or gagged the mains. The superheats were set at a lower pressure to maintain a flow through.


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