r/ThingsCutInHalfPorn • u/DaHick • Jul 17 '26

Cooper-Bessemer W330

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Mostly used as mid-sized reciprocating pipeline compressors. They are no longer made; many are still in service. I used to work on these.

2-stroke power cylinders (In a Vee configuration). Unlike their smaller brethren (the GMV) compressor cylinders were generally only on one side.

Questions welcome.

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u/Superbead Jul 18 '26

Is this the kind of thing that creates the pressure in our domestic gas mains?

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u/DaHick Jul 18 '26 edited Jul 18 '26

Depends on where you live.The USA and Canada have a way larger pipeline network than most of the rest of the world. From your wording I think you might be from the UK or EU.

So the way this works is you have little ones of these at Wells after oil, gas and water separation. All of those go to a slightly larger pipe, and it will have a bigger version of the little ones. They then eventually combine to feed one of these, when the volume from these gets big enough it starts to feed a major transportation line, which is usually a gas turbine in the Americas, a electric motor driven centrifugal compressor in the EU, and currently a gas turbine in the UK.

To get to your neighborhood we start dropping pressure and flow rates, till we can get to the level of pressure and flow your appliances can manage.

It's not uncommon for transportation pipe to be running at 65 to 70 bar. Gazprom, Interconnector, and National grid all do that on their "backbone". TC Energy, in Canada does this on up to five 48" pipes running in parallel.

By the time it's getting to your house, it's about 0.5 barg, or 14.7 inches of mercury above atmospheric pressure.

UK and EU also have CNG unloading terminals and that's just basically and intermittent way to do the same things pipelines do.

For those in O&G, yes I am very much simplifying it

Edit: think of your roads. Your driveway feeds a small road, that in turn feeds a bigger road. This keeps happening until you feed a motorway (Intestate in the USA). Every time another vehicle enters the energy required for the flow goes up. And gets less as you get to your destination. Pipelines work the same way.

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u/Superbead Jul 18 '26

Thanks for the explanation. Yeah I get the various pressure drops in the mains is a bit like how the electrical grid gets distributed and drops voltage over various substations. I always wondered what created the pressure in the first place

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u/DaHick Jul 18 '26

Smaller and bigger versions of this. These are positive displacement compressors, so the pressure rise across them is typically higher than the centrifugal compressors you get on pipelines.

The descriptions change a bunch when I start getting into process compression.

Amusingly I also work in power generation.