Branch Connections

[TugboatEng]

I have an already existing 5" cooling water pipe for a diesel engine that I need to add a 2" branch to. Flow is up to 10 ft/s in the 5" pipe and I need to divert about 25-40gpm out of it using a pump. Is there a best way to make this branch? Is perpendicular acceptable? Should I do a Y at 45 degrees. Should in project the branch pipe into the flow?

 

[MJCronin]

Use a weldolet or equal for the branch

MJCronin
Sr. Process Engineer

 

[DGrayPPD]

5" is an odd size. Can you tell us a little more about your existing pipe?

What is the pipe material?
Is this a butt weld system? Or a socket weld system?
Do you have a copy of the pipe spec for this line?
What does the existing pipe spec branch connection table call state? I wouldn't be surprised if they didn't for 5" NPS, but you could probably use the information from the 4" and 6" header size to make an assumption.

Yes, perpendicular branch connections are acceptable, and most times the norm. A 45 degree lateral connection may also be acceptable, dependent on a few factors. I'm not sure I fully understand your last question (should in project the branch pipe into the flow?).

Can you provide a sketch of the existing line for better visualization?

 

[LittleInch]

10 ft/sec is pretty fast but not exceptional.

Personally I would go for a reducing tee simply so you reduce the sharp edges you will get on a weldolet branch fitting, but if this isn't possible then just use a 90 degree branch fitting.

You don't need a protrusion into the main pipe.

Unless this cooling water has particulates in it I think you're over thinking this one.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[TugboatEng]

Thank you everbody for the responses. If you want tbe dirty details about what is going on here goes... I have a tugboat in my fleet that originally came with a 40kW diesel generator set. The boat has channel cooling where the engine coolant is circulated through channel iron welded to the outer skin of the vessel. A 19 ft channel was sufficient for a 40kW engine running at 180 degrees F. Fast forward 20 years and the old Detroit Diesel was yanked and replaced with a John Deere 4045 genset with a rating of 50kW. That system ran ok (there were a few hiccups) for 17 more years but the engine was required to be replaced for emissions reasons. We wanted to stick with the 4045 engine but it is now available in 65 and 99kW flavors. The 99kW engine is aftercooles and runs at a lower 160 degree F temperature. I did the math and realized that we only had about 25kW of heat rejection available at 160F and the 99kW engine requires 127kW. Despite my protest the company purchased and installed the 99kW unit. Now it overheats and trips from time to time and I'm stuck finding a solution. The main engine cooling system has a generous capacity and water returning from the channel cooling is a cool 105F. I am planning to branch in to the main engine cooling circuit and circulate its water through a brazed plate heat exchanger to assist the generator when needed.