BOOK IN SERIES
Linear Resistances in Parallel :
Figure 1.9 shows three electrical resistors in parallel and three hydraulic lines in parallel . Equations 1.7 and 1.8 show how to calculate the equivalent resistance in both cases .
The calculation in both cases is based on the following two facts :
• The effort variable across the resistive elements in parallel is the same .
• The total flow variable equals the sum of the flow variables through each element in parallel .
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Fig . 1.9 - Linear Resistances in Parallel
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| Global MDA Journal | NOV-DEC 2017
Nonlinear Hydraulic Resistances :
When a hydraulic valve performs its control function , fluid flow through the valve is accompanied by a pressure drop . Valve manufacturers express the resistivity of a hydraulic valve by a term called Valve Coefficient . Equation 1.9 shows the nonlinearity between the differential pressure ∆p across the valve and the flow rate Q of hydraulic fluid that has a specific gravity SG . A large valve coefficient means the valve passes a large flow for small pressure drop . www . ghmediabusiness . com