Branch Connection & Metal Filings

[Pulpboy]

I need to make a branch connection on a 6300 Kpa line. 18" main with a 0.937" wall and the branch will be 2". I know regular cutting devices can keep the coupon but what about the filings/ribbons. How do you stop them from entering the pipe. This is on a main line to a turbine in a vertical section so obviously we'll inspect it no matter what but how to stop the filings in the first place. Any ideas or equipment you know of?

 

[metengr]

We have done this before, and the only advice I could give to you is to have one person follow the in-place machining with a shop vac hose when you get close to breaking thru the main pipe wall. Yes, you might get a few small shavings in the pipe but this has worked well for us in the past.

The other option is to use a borescope device once the branch opening is finished and with a magnet placed on the end of the probe send it down the vertical section and pick-up any residual metal chips or turnings at the bottom.

 

[unclesyd]

No organic is going to make it, not 1000?C.
A lot of metals get squishy at this temperature and pressure, the only trouble is they don't come back.

What metal do you intend to use?
What is the gas?


If this was a wet tap there is a chip valve on the machine that helps flush out the chips.

We made a device that worked on the same principle with the magnets to use on 12" vertical steam lines. We had access about 30'-40' above the location of the tap by rolling a valve and were able to locate the magnets below the tap. As far as we know they were able to catch all the chips. This was before the borescope we only had a 36" Cystoscope

http://www.tdwilliamson.com/pigtdw/pipe_pig/pig_Magnetic.htm

Several years ago I sat in on a meeting where a hot tap company’s rep stated that they had a new style cutter that made very small chips. I can’t remember which one it was. I'll try to call as there is one person I know that was at the meeting and still works in the area to see if he can recall which one it was because they got the job.

 

[Pulpboy]

unclesyd

I'm not brave enough to try a hot (wet) tap on a 6300 Kpa superheated steam line so no the flushing wouldn't help. As far as catching the chips with a magnet we have no ability. There are no valves above allowing us access.

Metengr

I'll mention the vacuum to the contractor. I wonder if you could build a vacuum chamber and seal it to the bit. The just as it breaks through the 6 and 12 o'clock position the inrush might suck the chips in.

 

[metengr]

dosenbro;
You can try to build a small glove box to keep the chips from entering the main pipe run. Once you have penetrated the main steam line, I don't see why you couldn't snake a borescope with a magnet attached thru the opening to reach the bottom of the pipe run. The borescopes today have articulating heads to improve maneuverability.