Pre-context: "This can be visualised as a central core of diameter x, with typical a curved spiral wound around of thickness half x, although of course in reality it is made from one casting."

Quote: "This shaft fits inside a heavy duty rubber sleeve, of wall thickness typically x also."

Immediately followed by: "As the shaft rotates, fluid is gradually forced up the rubber sleeve."

Which precedes: "...as the shaft is "rolled" around the inside surface of the hole."

Real context: Pumps. Again. Only this time it's progressive cavity pump instead of centrifugal. Also, I found these today while at work because I was looking at what these pumps were. I almost fell out of my chair with my boss's boss's boss watching