4 way fitting in FRP pipe

[ManyQuestions123]

Hello guys,

I work as a maintenance engineer in a pulp mill. I'm planning on replacing a 65mm diameter FRP pipe that currently has a 4 way fitting shaped like a cross, but I need to change it to a 4 way fitting that looks like an L/T, but my contractor is telling me that this might be to fragile.
What's your opinion? The only standard I know of (din 16966) only refers to T shaped fitting (3 ways). Should I change the original 4 way to two TS? Or do something like an L/T 4 way fitting?

Thank you in advance.

 

[LittleInch]

Where are the flow paths?

Assume the straight line is the main flow, but do the flows enter or exit that main line?

All the same size pipe?

Never designed a cross ever or even seen one in real life.

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

 

[ManyQuestions123]

I attached a sketch of the piping. This is how it is originally.
Only one pump is working at a time.

I've also never seen a cross like this. All pipe diameter is the same.

 

[fel3]

Crosses are fairly common in water distribution systems and in house plumbing. However, I haven't worked with FRP, so I can't advise you there.

For water distribution systems, see, for example,

https://american-usa.com/products/ductile-iron-pipe-and-fittings/fittings/flanged-fittings/crosses

for 4-inch to 64-inch ductile iron crosses.

For house plumbing, I have seen galvanized fittings (e.g.

https://www.mcmaster.com/products/pipe-fittings/shape~cross/)

and PVC fittings (e.g.,

https://www.mcmaster.com/products/pipe-fittings/shape~cross/material~plastic-1/material~pvc/)

ranging in size from 1/2-inch to 2-inch, although larger fittings are available.

Back to your project: what is your reason for wanting to replace the cross with two fittings? Based solely on your sketch, I think a cross is probably better than two fittings would be, but you may have other reasons that would make two fittings better than a cross.

============
"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[ManyQuestions123]

This installation is pretty old, and it's used for pumping spent acid. The pipes are PN10 minimum.
The issue is that I need the piping coming from the pump on the right to come horizontally at the junction due to space reasons.
And the problem from the FRP perspective is tha the branches are made by cutting a hole in the straight pipe and "welding" another to create a fitting. And from what my contractor is telling me, doing an L in the 4 way fitting is too risky.

 

[TugboatEng]

I know what you mean by "welding" but you should be more descriptive because this "welding" is the questionable part of the process. The bonding can certainly be strong enough if the fillet is sufficiently large and the correct prep/materials are used.

Otherwise, can you cast a FRP block and drill it with ports to meet your dimension requirements? Socket glue it. Make sure to use a 100% solids resin for no shrinkage during gluing.

 

[Compositepro]

FRP is not isotropic. Fibers have direction.

 

[LittleInch]

OK,

I think what you're saying is basically a tee with a connection fixed to the side of the tee at right angles to the branch pipe?
Definitely never seen one of those, especially at equal size.

I can see why this isn't a great plan.

Two tees one after the other sounds a much better idea.

FRP fittings are a work of art at the best of times so just get two standard tees. I thought they made those around a mandrel, but they could be one of those unholy wrapping of fibre strips kind of thing.

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

 

[Compositepro]

Paper maché can be fun. But, two tees are probably more practical.