#158: Internal streamlining

When two pipes of different diameter are joined, internally there will be a step change in the bore.

Fluid passing down the pipe (either into the expansion or out of it) will take the opportunity to become fiercely turbulent and recirculate intensely in the ‘shelf’ region). This has the effect that to transport either gas or liquid will require a much bigger pump than if the pipe was of a single internal diameter. It might mean that for pumping crude oil, your pump triples in price or in a domestic heating system, the existing pump simply fails to deliver enough flowrate.


Ideally, all pipework in a given system would have one bore, or at least have only smooth changes in diameter. Often, that’s not how things work out…engineering conical sections of arbitrary size, in-situ, which are also pressure-rated is a tough job.

Today’s invention is a way to smooth out internal step changes in pipework. When two different size pipes are joined (using reliable, simple bolt-through flanges), spin the jointed section about the longitudinal axis (by using eg a drilling rig for large-scale hardware). Whilst spinning, pour in epoxy material of the type normally used to smooth the internal surfaces. This will be thrown to the corners of the shelf region and take up a natural streamlined shape (think of stirring a cup of tea in a tall cup, or of the surface profile of water going down a plughole),

When the cement has set, the streamlined pipe section can be inserted, as normal, into the main plumbing.

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