|
Pump Flow Graph What is a flow graph and what does it show? The graph Below is a fictitious flow graph. You should find a flow graph on a box for a pump before you buy it. At the side it says head, in feet. This is another way of saying how high the water can be pumped to. Across the bottom it says litres / minute. This is how many litres can flow in a minute. Please be aware the above is true, but the figures only apply to this fictitious pump. Each pump has its own flow graph.
Use Now you know what its makings are, what can you do with it? You can tell if a pump will be able to pump as expected. It will save you buying a pump that is too small for the task. How? Lets say we have a waterfall that is 15 feet from the water surface, how much water will be available? First you look at the side axis for 15 feet. You then follow this line until it meets the intersecting line (Blue one in this case) You then follow this down to the bottom axis. You will arrive at the line just before 25. This line represents 20 (On this graph it does) So you now know that at 15 feet up you will have 20 litres / minute available. Like wise at 8 feet you will have 75 litres / minute available. What else Similarly if you have a waterfall that requires 50 litres / minute at 15 feet you will see this pump can only supply 25 litres / minute, which is not what is required, so this pump is not suitable. |
