In the fifteenth century the Swiss scientist Daniel Bernoulli learned that the combination of head and velocity was a constant throughout a piping system. He then wrote the formula showing the relationship between this liquid velocity, and resultant head. As many of you know, I often quote this formula in my pump and seal schools. My students have heard me quote this formula as the basis for my statement that you can estimate the shut off head of a 1750 rpm.
Velocity is a measurement of speed using distance and time as the variables.
Now we will solve the formula. It is a little trickier in the metric system. Instead of using millimeters when measuring the impeller diameter, move over two decimal places and use decimeters instead. It will make the calculations a lot simpler because you will be using more convenient, larger numbers. The pump suction pressure gage reads 20 psi.