Search found 63 matches

by froya66
Mon Mar 08, 2021 1:17 pm
Forum: Technical - Engines and Boilers
Topic: Removing boiler tubes
Replies: 23
Views: 12995

Re: Removing boiler tubes

Hi Why do you think that the tube sheets will deform more when pressurised from the inside of the gas path? The force will be the same as if pressurised from outside, hold in position by the tubes. The longitudinal forces on the tubes will be pull in stead of trust, but that should not worsen anythi...
by froya66
Mon Mar 01, 2021 1:15 pm
Forum: Technical - Engines and Boilers
Topic: Removing boiler tubes
Replies: 23
Views: 12995

Re: Removing boiler tubes

Thanks for all your comments. We will discuss with the boiler owner how he prefer the job done - with or without copper sleeves. Under all circumstances we intend to fabricate a big blind flange to fit the bottom of the firebox. In this manner we can pressure test the new tubes, by water filling the...
by froya66
Tue Feb 16, 2021 12:54 pm
Forum: Technical - Engines and Boilers
Topic: Removing boiler tubes
Replies: 23
Views: 12995

Re: Removing boiler tubes

Comming back on the water tube boiler, we have discovered that each tube is surrounded by a thin-walled copper bushing in the tube sheet.

Any idea what could be the reason for such a design?

The holes are reamed together, so the reason is not to even out any angle deviation between the two holes
by froya66
Sat Dec 05, 2020 9:25 am
Forum: Technical - Engines and Boilers
Topic: Removing boiler tubes
Replies: 23
Views: 12995

Re: Removing boiler tubes

Thanks for the advises guys.
Just a commet - the tubes are not horisontal - I gues sloping some 4 degr.
Have a nice weekend
Jørgen
by froya66
Thu Dec 03, 2020 8:12 pm
Forum: Technical - Engines and Boilers
Topic: Removing boiler tubes
Replies: 23
Views: 12995

Removing boiler tubes

Hi I have to replace a number of 40 mm boiler tubes in a special water tube boiler. See picture. The outer and the inner barrel (flue gas uptake) is bolted together. I can cut all the tubes inside the flue gas pass - but I wonder how to remove the remaining pieces from the tube sheets - without dama...
by froya66
Wed Feb 08, 2017 11:02 pm
Forum: Technical - Engines and Boilers
Topic: New VFT boiler for Frøya
Replies: 23
Views: 21585

Re: New VFT boiler for Frøya

Hi Guys Thanks for all your comments regarding steel versus copper. I might get so interested in this question that I produce a small test rig, in order to actually measuring the difference - specifically pointing against the VFT boiler. I shall give you a full report - if not my laziness kills it b...
by froya66
Mon Feb 06, 2017 10:56 pm
Forum: Technical - Engines and Boilers
Topic: New VFT boiler for Frøya
Replies: 23
Views: 21585

Re: New VFT boiler for Frøya

Hi steam boaters Long time no post, but now it’s time to roll in the copper tubes. This raise a discussion among the Danish steam boaters about copper versus steel when it comes to heat transfer. All of us are of cause aware of the increased heat conductivity when using copper, but it seems to play ...
by froya66
Wed Mar 23, 2016 11:22 pm
Forum: Technical - Engines and Boilers
Topic: New VFT boiler for Frøya
Replies: 23
Views: 21585

Re: New VFT boiler for Frøya

After a long pause, the boiler works has finale come to live again. One of my very welding skilled colleagues has started to TIG all the bottom strings and I finish with the less complicated cover welding with shielded basic electrode. First, the tube plate was welded to the firebox. Fire door coami...
by froya66
Sat Jan 23, 2016 9:45 pm
Forum: Technical - non Engines and Boilers
Topic: Propeller shaft
Replies: 2
Views: 5772

Re: Propeller shaft

Thanks Bart

That was very helpfull :D

Best regards
Jørgen
by froya66
Thu Jan 21, 2016 7:34 pm
Forum: Technical - non Engines and Boilers
Topic: Propeller shaft
Replies: 2
Views: 5772

Propeller shaft

Is there a rule of thumb regarding diameter of propeller shaft.

Propeller size - 19 X 23", 450 - 500 RPM, 4 SHP. No heal - no intermidiate bearing - propeller direct at stern.

Will 3/4" do or should it be 1"

Jørgen