Flange connections vs. pip couplings
Flange connections vs. pip couplings
(OP)
For a while now, I'm wondering about the relative pros and cons of pipe couplings (like this: https://www.straub.ch/fileadmin/Straub/Downloads/D...) vs. flanged connections in piping.
The applications I'm dealing with are wastewater, water, maybe sludge at up to piping PN16 and temperatures in the 0°C - 100°C range; and sewage gas in a pressure range up to 100mbar and the same temp. range.
- From actual quotes from contractors, I see no huge difference in price between a flange connection (consisting of collars and loose flange or two fixed flanges and bolts/work) and a coupling.
- Couplings allow some play in distance between the pipes (up 45mm in large pipes if I read the sheet correctly and use the extra band)
- Installation time should be far quicker if I consider the time for welding
The applications I'm dealing with are wastewater, water, maybe sludge at up to piping PN16 and temperatures in the 0°C - 100°C range; and sewage gas in a pressure range up to 100mbar and the same temp. range.





RE: Flange connections vs. pip couplings
Flanges - two welds, two flanges, bolts, gasket.
Key issues
Your seal is wholly dependent on the "rubber" seal
I notice it says "In case of leakage..." tends to mean it happens a lot
The axial force capability is terrible and hence you need anchors and thrust blocks at all changes of direction
They might claim to be axial restraint pipe but I couldn't see a max axial force anywhere and whatever it is it will be a lot less than a weld or a flange
expansion capability will be limited
Bending force capability is also terrible
Don't know where you get 45mm from. With strip insert it says 35, but is this really needed?
The pipes it is attached to will need to be clean, very round and cut straight. Installation time will be lower, but is it that important?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Flange connections vs. pip couplings
RE: Flange connections vs. pip couplings
I've seen these in wastewater (never gas!) installations designed by other firms and so I wonder if this is an idea worth copying.
I'm right now in an early planning stage for refurbishments for a sewage gas installation. Keeping the time the installation is out of commission short is a bonus.
LittleInch,
It can be neccessary to have flanged connections, there's places you could weld a collar or flange but you can't weld a large pipe.
Your other points are noted.
RE: Flange connections vs. pip couplings