Over the last two weeks we covered the two most basic ways to balance flow through multi-bank arrays (outlet temperature measurement and reverse return piping). These methods of balancing flow are simple and robust but each have limitations. If you have a multi-bank array that doesn’t lend itself to either of the two previously mentioned methods then you are left to use balancing valves to achieve proper flow.
The basic concept behind a balancing valve is that any valve will generate a given pressure drop at various flow rates. A balancing valve works by having ports for measuring the pressure both before and after the valve. The difference between these measurements is cross referenced to a graph that shows the flow rate –vs- pressure drop. Once you have measured the pressure drop you are then able to find the flow rate on the graph. A good quality balancing valve will have the ability for fine tune adjustment. The process of setting the balancing valves in large systems with many banks can be time consuming but it does provide a proven means to guarantee consistent flow.
