Dilemmas in Physics … Solids Size vs Flow Rate
It has proven to be a source of frustration in the pumping world of how to match solids capacity to actual flow rates using a centrifugal pump, the old go-to in industrial sump pumps. The term “velocity head machine” applies well to a centrifugal pump because the pump has to create internal velocity to impart enough energy to the liquid to make it flow with enough pressure to push the fluid to where it is going.
A simple explanation of this process (there are exceptions to almost everything) requires that the impeller spin fast enough to get the fluid velocity up but the space between it and the pump casing be big enough to pass the diameter solid needed. That’s the rub; when you put velocity and area together, you get flow rate, and the bigger each parameter is, the more flow you get. Need higher pressure? Then you have to bump up velocity because the gap has to stay big enough to pass the solids.
For example, say you want to pump an orange instead of eating it. The orange is 3” in diameter, so the passage in the pump needs to allow for 3” and you need to pump it up an elevation of 100 feet. That requires plenty of velocity to convert into 100 ft. of pressure, and now you have lots and lots of water flow rate to get that orange 100 ft. up.
What if you don’t want to pump so much water or don’t have it to begin with? This is the reality in a large number of industrial sump pump applications. The big solids are getting to the sump, but the flow rate is low to medium. When you put in a centrifugal pump big enough to move those solids, the flow rate is grossly oversized to what the sump receives.
Enter a different technology, simplicity. What if you can completely separate flow from solids size? This is what the Pitbull Pump does. The passage through a Pitbull industrial pump can be selected to easily pass the solids – and instead of needing velocity to make pressure, the pressure is directly applied to the liquid with compressed air/gas at whatever pressure is needed. So that 100 ft. discharge head is just a setting, and the same Pitbull can pump that same solid at 20 ft., 100 ft. or 200 ft.
In the end, this is the solids advantage of our industrial sump pumps, the ability to pump all sorts of debris (including stringy … a whole other centrifugal dilemma) and solids sizes at the real world flow rates of the sumps that receive them. For high flows and big solids, the centrifugal pump is generally the correct tool for the job, but when those parameters don’t match (as they often don’t), there is a better way.
Some examples of Pitbull solids apps: waste pulp, chicken gizzards, coal chunks, gloves, rags, paunch manure, spent grains, whole vegetables/fruits, raw sewage, sticks/leaves/rodents, clotted blood, cattle brains/spinal cords, hide/flesh, waste produce – there is a large range of great applications from the mundane to the weird, including plain old sumps where no one wants to worry about a pump plugging.
Whether your application is weird or mundane (or something in between), a Pitbull industrial pump is likely the best answer for your pumping challenges. Contact us now for the assistance you need.
- Posted by Madelyn Vetter
- On April 6, 2017