WorldWide Drilling Resource

69 WorldWide Drilling Resource ® MARCH 2014 !0 0'$ '$.!0,+ ,0$) ,+%$.$+"$ $+0$. $# $$. !+!#! -.() $"'+("!) $//(,+/ 5 +0$.0!(+*$+0 / $&1)!0(,+/ !+# +%,.*!0(,+ 5 ++1!) $$0(+& .())(+& (&/ !+# $2 $"'+,),&4 (/-)!4/ ,. ,.$ +%,.*!0(,+ ,+0!"0 !.,) !./,+ ',+$ *!() !22#! 3-),.+$0 ",,* Terms Part 3 by Bill Corey Pentair Water Training Institute This month we are going to discuss Cavitation. This is one of the most mis- understood terms in our industry. I give a test before every Factory School that asks the question: What is cavitation? Answers vary, but most say something to the effect that it is air in the pump or system. I want to point out, an air bubble in a pumping system will compress, and if it does not cause loss of prime, it may get chopped up in the impeller. But when it comes out on the other side, it is still air - perhaps very small bubbles, but still air. If you have ever installed a jet pump, when the water first comes out it is a very milky color. This of course is the air chopped into very small bubbles; and when left to sit for a while, they all collect together and exit the glass. What is left is nice clean water. That of course is an air bubble. Avapor bubble is what you get when you convert liquid water to a gas (water vapor). When it comes under pressure, it collapses and sends out a shock wave causing damage. But what hap- pens when liquid turns to vapor? How does that process take place? Some people call it flashing, the conversion of a liquid to a vapor. If you were to place water in a pan on a stove and turn it on, once the water hits the correct temperature it flashes or boils. It converts from a liquid to a vapor. Re- member, at sea level we have 14.7 psi pushing down on us, and most agree when the temperature of the water gets to 212°F (100ºC) the water converts from a liquid to a vapor. What most don’t understand is if you lower the pressure over the liquid, you can cause it to convert at a much lower tempera- ture. For example, water in Denver, Colorado, boils at about 201°F (94ºC), only 12 psi over it. On the side of a macaroni box it says if you are going to cook it at a high altitude you must cook it longer. Why? Because at 10,000 feet the air is thinner, so there is not as many molecules. This means water will boil at about 185°F (85ºC). Lower the pressure to about .4 psi and you can turn liquid water into vapor at 70°F (21ºC). More next month. Bill Bill Corey may be contacted via e-mail at admin@ worldwidedrillingresource.com In Memoriam David Perez (1966~2013) We were extremely saddened to hear of the industry’s loss of our friend David Perez of Amarillo, Texas, who passed away suddenly on December 27, 2013. He was a territory sales manager with Gicon Pumps & Equipment, having been with the company for 15 years. You could always recognize him at trade events by his black hat. This photo was taken at last year’s Oklahoma Ground Water Trade Show by Kathy Heinrich. Born in Lockney and raised in Plainview, David later moved to Amarillo after marrying the love of his life Terry. Making friends was easy for David, and he could always be counted on when someone needed help. He was very active in his church and community. Grand Knight of Blessed Sacrament Knights of Columbus Council 7573 and a member of Fourth Degree Assembly 1090 of Amarillo, he was also president of the finance committee at Blessed Sacrament Catholic Church. David enjoyed the outdoors hunting and fishing, and spending time with family and friends. David is survived by his wife Terry and daughters Casandra, Chelsea, and Christiana, along with his mother, brothers, and sisters. Our sympathies go to David’s family, friends, and colleagues. He will be greatly missed. Don’t miss the May issue deadlines! Space Reservation: March 25 th Ad Copy - Display & Classified: April 1 st