Head size correlation with

In-house correlation of pumps should be made using gpm vs. cost with head as a parameter. These should result in step functions, since one size pump with different impellers can serve several flow rates and heads. Different correlations should be made for each type of pump. The price of a vertical multistage pump may be quite different from a horizontal splitcase multistage pump. A sump pump with a 15-ft drive shaft would cost more than a single-stage horizontal pump with the same gpm and head. 

Humphrey I want to come back to the question of correlation and causation. It s tempting of course to assume that a relation between two variables is causal when we can see how it would work, but to assume it s a mere correlation when we can t see it. So, when we find that IQ correlates with brain size or head size, we think that s probably because large brains do indeed cause high IQ. But when we find IQ... 

Gutmann R, Leunig M, Feyh J, Goetz AE, Messmer K, Kasten-bauer E, Jain RK (1992) Interstitial hypertension in head and neck tumors in patients correlation with tumor size. Cancer Res 52 1993-1995... 

Size, rotating speed, and efficiency correlate well with the available isentropic head, the volumetric flow at discharge, and the expansion ratio across the turboexpander. The head and the volumetric flow and rotating speed are correlated by the specific speed. Figure 29-49 shows the efficiency at various specific speeds for various sizes of rotor. This figure presumes the expansion ratio to be less than 4 1. Above 4 1, certain supersonic losses come into the picture and there is an additional correction on efficiency, as shown in Fig. 29-50. 

It is often used by designers in sizing and selecting the type of pump or compressor. The performance of centrifugal pumps is related to a parameter called specific speed. It is a correlation of capacity, head, and speed at optimum efficiency that classifies pump impellers with respect to their geometric similarity. Specific speed is a number expressed algebraically as ... 

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