The other night I was babysitting my grand-kids and they asked me to read them a story from their favorite book Piping System Fundamentals. So I asked my middle grandchild, what part of the book she would like me to read. She said the part about balancing the energy usage within a pumped system and the need to identify and eliminate excess pump head. When I started reading, she said “No Pop-Pop not with those words, make it into a story with kings, and animals.” Well I knew I needed to bring out my old French friend Henry Darcy to create another “Darcy’s Fable.”
The Story of the Elephant King and the Busy Beavers
Once upon a time, there lived an Elephant King, who liked to provide his subjects with all the best the kingdom could offer. The King decided that for the kingdom to grow and prosper he would need to bring water from Lake Lilly, the giant water hole in the center of the kingdom, to all the cities and villages.The first order of business was to get the Zebras together to plan the water system for the future and make sure it wasn’t too small. The Zebras came up with their estimate and then doubled it just to be on the safe side. They forwarded their estimate to the Wart Hogs to come up with a design. (My grandson thinks Wart Hogs are nice and wants them in every story!) The Wart Hogs did all their calculations, and since they were planning for the future they too added an ample margin for future growth.
As the system was built, everyone was excited. The Squirrels, having a knack for saving, were in charge of kingdom finances. Since the Squirrels had to pay for the project out of the royal treasury, they were starting to get concerned about the project costs. The project went ahead and was finished on time but over budget. The water pumps were big and they took large teams of Horses to run them, but they were bright and shiny. Everyone was impressed with what had been built. Once the water system was finished and the pumps started, there was plenty of water everywhere around the kingdom. In fact, there was too much water in many locations and some of the villages had problems dealing with the water.
In one farming village, there were floods in the fields but the resourceful farmers planted rice in the fields instead of wheat to try and “fix” or “cover” up the overabundance. In other villages, the excess water went into the streets making it difficult to travel, but it was quickly diverted by the Hippopotami to existing streams that lead back to Lake Lilly. Over time, all the startup problems were solved and the system worked. As the wise Elephant King envisioned the kingdom prospered.
After a couple of months, the Squirrels approached the Elephant King and said that the water project cost twice as much to operate than originally planned. But since the kingdoms productivity increased there was enough in the royal treasury to pay for the increased operating cost.
In the summer months, when the water was needed the most there were parts of the kingdom that didn’t have enough water. The King decided that something needed to be done so he brought in the Busy Beavers to look at the system to see what could be done.The first thing the Beavers discovered was that some areas in the kingdom got too much water while other areas more distant from Lake Lilly didn’t get enough. The Beavers busily set about to plug some of the pipe outlets in the areas that had too much water. As they started plugging the pipelines close to Lake Lilly, they started getting more water to the more remote locations of the kingdom. As they worked their way out from Lake Lilly, they found that all the pipelines needed to be partially plugged to prevent flooding. Soon the Beavers found that over time, the plugs they placed in the pipelines to balance the flow would spring leaks requiring continual repairs.
After talking to the Squirrels about the operating costs, the Beavers discovered the cost to operate the large Horse driven pumps continued to climb. It seemed the raceway the Horses ran on to drive the pumps was also beginning to wear out. When the dirt raceway was replaced with a stone raceway, the Horses’ shoes wore out much faster and their hooves were splitting, increasing the system maintenance cost. Neither of those solutions worked!
Then the Beavers put two and two together and determined that the pump was too large for the needs of the system. After reviewing the pump curve and performing a few pump affinity speed calculations, they determined that if they replaced the fast Horses with smaller and slower Goats the pump would develop less pressure and would stop blowing out the plugs. After replacing the Horses with Goats, they rebalanced the system and all was well in the royal water system. The Beavers were able to reduce the cost to run the pumps as well as practically eliminate all of the breakdowns and maintenance troubles.
The Elephant King was so happy that the system worked that he had a royal dinner for the Beavers and everyone lived happily ever after.
THE END
My granddaughter was so happy about the story she said “See Pop-Pop, if you optimize a pump, you can reduce your capital costs, operating cost, and maintenance costs while increasing system reliability. I really like stories with happy endings.”
