Can my total dynamic head (TDH) be more than the “Rated Head” on the pump?

Question

I have just received a recommendation to use a pump with a "Rated Flow" of 1cu.m/h and a "Rated Head" of 91m. I am realizing I am actually not familiar with these two terms (Rated Flow and Head).

My total dynamic head is a little more than the "Rated Head" (It's 110m), and I intend to pump at a flow rate a little less that the "Rated Flow" (I intend to pump at 0.5cu.m). Both these values--though not very efficient--fall well-within the constraints of the pumping curve. Should I be worried by the "Rated" labels? What exactly do they signify?

Answer 1

In this case, "Rated" refers to the design point of the pump. Just look at your pump curve, there is no way the pump's shutoff head is 91 m at a flow of 1 m^3/h. That is right in the middle of the curve. "Rated" is referring to the design criteria used to select the pump.

You need to find more information for this pump to really address your question. The curve that you attached does not give a maximum head or minimum continuous stable flow. There is also not a line for maximum flow, although you can just assume that you need to stay away from the end of the curve.

If you are really going to run this pump at 110 m, you may want to select a different pump. You will be running this pump way up on its curve. Plus, you are going to get a really poor efficiency doing that (which also is not provided).