[brian_]

... there was a watering system that used 5 pumpr to water all the batteries. These are rather interesting pumps - see pics..I removed the top plate and found this inside. The tubing is a very flexible silicon tube and the cross bar with roller wheels at each end rotates and squeezing the tube pushes the water along the tube. I have never seen a pump like this before.

That's a peristaltic pump, a type which is commonly used to precisely meter liquids and to handle fluids for which any leakage is unacceptable. Have you seen those computerized boxes on poles controlling the flow of intravenous fluid into patients in hospitals? Those are peristaltic pumps.