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Terms Part 10 by Bill Corey Pentair Water Training Institute Daniel Bernoulli was a scientist born in February 1700, who died in March 1782. He was a mathematician and physicist who wrote some of the laws on water movement which we still use today. I often talk of how he said water is noncompressible, and what this means to us in the water-moving industry. The formula I share with my students is: (P 1 ÷p+V 2 1 ÷2G+Z 1 ) = (P 2 ÷p+V 2 2 ÷2G+Z 2 ) What it all means is: P is the pressure gauge reading at a point in your piping system. p is the density of the liquid being pumped (of course if you put fresh water in, you get fresh water out, so in our “user friendly” version we leave this out). V 2 is the velocity of the water squared. 2G is the Universal Gravitation Constant times 2. Since we are talking about 32.2’/sec² (32.2 feet per second squared) you could use the number 64.4. Z is the interesting part of this equa- tion as it means the height above or below a reference point. Okay, I mentioned the “user friendly” version which looks like this: (P+V 2 ÷2g+Z) = Constant In other words, if I have a pressure gauge at two different points in a piping system, the gauge pressure will be dif- ferent, but the total energy at each point must be the same. Example: The point here is this, if you have water moving through a small pipe and then move that same amount of water through a larger pipe, there has to be a velocity change which directly affects the pressure. So what I try to help people understand is if you use larger pipe in a system, there will be a benefit of higher pressure. This can also lead to reduced horsepower to accomplish the job. Smaller systems, of course, see less of a reward than larger systems would, but there is a savings nonethe- less. I tell my students the hole in the pump is not necessarily the pipe size you should be using. Bernoulli’s Law verifies that while the pump can only build this much pressure, if you use larger pipe on the discharge side, you may get more pressure for your system. One very important fact I also share is the discharge pipe should NEVER be larger than the suction pipe. They can be the same size, but you never want the discharge pipe larger. More on this next month. Bill Bill Corey may be contacted via e-mail at admin@ worldwidedrillingresource.com 65 WorldWide Drilling Resource ® OCTOBER 2014