Thread: Whisperings

Hi.
Totally agree re multiple joints but sparge tubes are on the boiler side of the flange (unless he is talking about the feed line to the sparge) and a leak will only end up inside the boiler where it is destined anyway , another issue that may preclude this fix is that the reducer increases the diameter at the back of the flange and may not fit through the bore of the boiler pad , as Phil said these sparge pipes are normally welded to the flange but he is trying to avoid a pressure weld that he is not ticketed to do and so using this method.
Another way of doing this is to weld the sparge tube to a standard width flange , use longer studs and sandwich this flange between the feedwater pipe flange and the boiler pad , this would mean that the weld was not a pressure weld and within his capabilities.
If I could supply a sketch to make this easier to understand I would but my computer skills don't stretch that far , if Phil understands my meaning maybe he could sketch something up or show us his intended installation.
Jim.

Originally Posted by Michael G

In Phil's case as the public view the machines there may be atheistic reasons too.

Personally, I'm just agnostic about steam engines....

PDW

Stix and Michael,
I would swear you two are standing in the boiler house.
You have just about covered every conversation we have had about this installation.
I will expand further tonight when I get home, meanwhile, I will take some happy snaps to help me explain.

Phil

Originally Posted by PDW

Originally Posted by Michael G

In Phil's case as the public view the machines there may be atheistic reasons too.

Michael

Personally, I'm just agnostic about steam engines....

Oh Bugger. that should have been aesthetic.

Michael

Originally Posted by Michael G

Oh Bugger. that should have been aesthetic. Michael

I'm surprised I didn't pick that one up Michael.
Touché' Pete. Lol

Phil

Originally Posted by Michael G

Oh Bugger. that should have been aesthetic.

Michael

Yes, I am sure Phil believes in the god of steam... Who knows what secret rituals the steam workers get up to.. secret handshakes and all that.. I am sure he could tell, but then we would have to die..

Originally Posted by Michael G

A joint is a potential leak/ failure point so they are avoided wherever possible (we have the same problems at work with hydraulics). A stack of fittings may get you out of trouble as a short term fix but would be considered bad practice as a permanent installation if there was a simpler alternative. I'm not sure about steam but there may even be rules in the appropriate codes that formally disallow doing that sort of thing.

In Phil's case as the public view the machines there may be aesthetic reasons too.

Michael

Hi Michael
correct on all fronts.
The more joints, the more potential leaks and the more work at inspection time. We have a rule at work that there 'will' be no leaks so it is good practise to lose potential areas in the first place.
There is a rule with regard to stacks of fittings that come off the boiler. I don't know the actual wording but stop valves, check valves safety valves etc. must be connected directly to the boiler with a minimum of fittings.
With regard to the aesthetics (lol) we try to put it back to original but the pics of its previous installation show a pretty ordinary setup of the pipework so we are going with a more legal way.

Originally Posted by stix012

Hi.
Totally agree re multiple joints but sparge tubes are on the boiler side of the flange (unless he is talking about the feed line to the sparge) and a leak will only end up inside the boiler where it is destined anyway , another issue that may preclude this fix is that the reducer increases the diameter at the back of the flange and may not fit through the bore of the boiler pad , as Phil said these sparge pipes are normally welded to the flange but he is trying to avoid a pressure weld that he is not ticketed to do and so using this method.
Another way of doing this is to weld the sparge tube to a standard width flange , use longer studs and sandwich this flange between the feedwater pipe flange and the boiler pad , this would mean that the weld was not a pressure weld and within his capabilities.
If I could supply a sketch to make this easier to understand I would but my computer skills don't stretch that far , if Phil understands my meaning maybe he could sketch something up or show us his intended installation.
Jim.

Hi Jim
This particular joint is on the outside of the boiler but even saying that, the actual sparge pipe even though it is on the inside of the boiler shouldn't leak as any leak from a joint creates what is called 'wire drawing' which basically is gouging of the fittings where the leak is. I don't like that as it just means more repairs further down the track.
Sandwhiching a flange between two flanges is a good idea and it how the feedwater inlet from the pumps is done but extra gaskets and a bit fiddly to set up with a long pipe (sparge) hanging off one end.
I have never been a fan of welding this and that as I am normally the one that has to repair or replace, being a maintenance fitter, and the easier I can make it, the better I feel. Easier to unbolt than cut and shut, well for me it is. Spanners are cheaper than welding gear
You mentioned the bore of the pad on the boiler and if I had brought the pics home with me I would show you the situation (which at this stage will be tomorrow morning). I am going to have to fire up the die grinder and enlarge it to remain in spec

Originally Posted by .RC.

Yes, I am sure Phil believes in the god of steam... Who knows what secret rituals the steam workers get up to.. secret handshakes and all that.. I am sure he could tell, but then we would have to die..

Ya kiddin' me Richard, you make it sound like there could possibly be another god other than a steam god or "aqua dais" as we call him. In fact we honour our god every morning in a ritual we call "putting steam on line"
Now I have to kill you.

Phil
PS pics tomorrow

Hi all
here are the pics I promised. One of them is a bit ordinary so I will take a better one later to illustrate what is going on.
I have a minimum spec I want to keep to which is the OD of the rated socket we are using on the ancilliary fittings.
To do this I will have to gouge out the hole a bit in the flange on the boiler and maybe a bit more as it seems the hole is also offset to the PCD ( Pitch Circle Diameter) of the holes.
The minimum spec is the long spigot on the flange I am making as it holds the sparge pipe unsupported in the boiler.

Phil
ps I have an interesting story for later (today hopefully) on the nightmare that is tapping a BSPT (British Standard Pipe Taper) thread in the flange I am making. This one is really driving me to insanity.

Phil
IMG_7196.JPG IMG_7201.JPG IMG_7202.jpg

Hi Phil, is it possible to mount the flange in a 4 jaw and measure the offset required, working from the bolt holes?
Kryn

Hi Phil,

Is the offset hole intentional or slack forging?

It doesn't look to be very far off centre, does the offset really matter?

Ken

Originally Posted by KBs PensNmore

Hi Phil, is it possible to mount the flange in a 4 jaw and measure the offset required, working from the bolt holes?
Kryn

I thought about that Kryn but the flange on the boiler is (at the moment) a permanent thing and the flange I am making is replaceable. It is better to machine my part up concentric which is easier should it have to be replaced in the future. If I grind out the bore of the flange on the boiler it will create less problems in the future as well.

Originally Posted by neksmerj

Hi Phil,

Is the offset hole intentional or slack forging?

It doesn't look to be very far off centre, does the offset really matter?

Ken

I think it is a bit of both Ken, it maybe a case of 'she'll be right mate' which happily, is 'not' how we do things
We will never know if the person that put the flange on actually knew what he was doing...or cared
At least doing it our way will allow me to sleep at nights.

Phil

Now, the insanity that is, tapping a BSPT thread.
Originally I was going to tap the hole BSPP which is paralell. I borrowed a tap and it had BSPF on it. I looked up the tapping size for BSPF and bored the hole out to suit and tapped the hole. I could have thrown the nipple into the threaded hole from across the room. The boss and I both agreed it would be best to start the process again but this time tap the hole BSPT which is the tapered version.
BSPF after looking closely at the charts is for structural type fittings and not pressure pipe and BSPP is for pressure pipes and has a different, and smaller tapping size
Anyways, as we don't have a reamer to suit the taper I decided to bore the hole out and in my efforts to not get it wrong again I stopped and thought about it.
There are no specs on the size of the hole at the large end or the small end. but there is reference to the major diameter of the pipe thread 3/8" up the taper from the end of the pipe.
Seeing as there is supposed to be 100% engagement when tight I decided to make a gauge up and machine the bore to that spec.
While researching I found a lot of discrepancies with regard to standards
One publication had the thread angle at 47 1/2 deg, the others at 55 deg. One had the thread perpendicular to the centreline of the pipe and another had the thread perpendicular to the taper.
Thankfully they all had the taper at 1 in 16.
Most American publications give a cursory mention of British threads and obviously are happy to publish mistakes like 47 1/2 deg thread angle
To buy the relevant British standard was going to cost 108 pound from England so not gunna happen.

Phil
IMG_7210.jpg IMG_7205.jpg IMG_7213.JPG IMG_7215.JPG IMG_7220.jpg

Hi Phil,

I'm no expert so this is from memory.

The female bore is parallel and not tapered, the thread is a 50 degree Whitworth form. A lot of people seem to mix up the American NPT with the BSPT. If I recall correctly the NTP is a bigger diameter for a given pipe size. The figure of 65% for something sticks in my mind but I can't remember why.
The few pipe joints that I recall were lathered to the hilt with "Boss White" thread paste because they always seemed to leak. I do remember the pipe breaking off on an odd occasion when trying to tighten it up to stop it dripping.

HTH

Originally Posted by Steamwhisperer

Now, the insanity that is, tapping a BSPT thread.
Originally I was going to tap the hole BSPP which is paralell. I borrowed a tap and it had BSPF on it. I looked up the tapping size for BSPF and bored the hole out to suit and tapped the hole. I could have thrown the nipple into the threaded hole from across the room. The boss and I both agreed it would be best to start the process again but this time tap the hole BSPT which is the tapered version.
BSPF after looking closely at the charts is for structural type fittings and not pressure pipe and BSPP is for pressure pipes and has a different, and smaller tapping size
Anyways, as we don't have a reamer to suit the taper I decided to bore the hole out and in my efforts to not get it wrong again I stopped and thought about it.
There are no specs on the size of the hole at the large end or the small end. but there is reference to the major diameter of the pipe thread 3/8" up the taper from the end of the pipe.
Seeing as there is supposed to be 100% engagement when tight I decided to make a gauge up and machine the bore to that spec.
While researching I found a lot of discrepancies with regard to standards
One publication had the thread angle at 47 1/2 deg, the others at 55 deg. One had the thread perpendicular to the centreline of the pipe and another had the thread perpendicular to the taper.
Thankfully they all had the taper at 1 in 16.
Most American publications give a cursory mention of British threads and obviously are happy to publish mistakes like 47 1/2 deg thread angle
To buy the relevant British standard was going to cost 108 pound from England so not gunna happen.

Phil
IMG_7210.jpg IMG_7205.jpg IMG_7213.JPG IMG_7215.JPG IMG_7220.jpg

Like I said, weld it - done & dusted. Could have done half a dozen for spares in the same time you've been making one to the wrong size )

OK you have stupid rules to abide by, get a certified welder to weld it. I could do it, I've been certified...........

............ but they made a mistake and let me out after a while.

If we were talking 300 bar pressures I might not be quite so cavalier though.

PDW

Originally Posted by PDW

I could do it, I've been certified....................... but they made a mistake and let me out after a while.PDW

You're from the same place as me .
Kryn