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Selecting a well pump

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Four categories of questions that a conscientious pump buyer ought to consider in the process of selecting a well pump

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Selecting a well pump

  1. 1. Selecting a Well Pump Brian Gongol DJ Gongol & Associates, Inc. February 2, 2018 Iowa Water Well Association Annual Conference Altoona, Iowa
  2. 2. [Part 1] Categories
  3. 3. Vertical turbine pumps
  4. 4. Submersible turbine pumps
  5. 5. [Part 2] Basic constraints
  6. 6. Flow
  7. 7. Head
  8. 8. Physical shape and size
  9. 9. Laws of physics
  10. 10. [Part 3] Other limitations
  11. 11. Power
  12. 12. Hydraulic thrust
  13. 13. Downthrust
  14. 14. Shaft elongation
  15. 15. [Part 4] Additional considerations
  16. 16. Power source
  17. 17. Discharge head
  18. 18. Lubrication
  19. 19. Part 1: Categories
  20. 20. 1.1 When to choose a vertical turbine
  21. 21. Default option for wells
  22. 22. Motor accessible for maintenance and repair
  23. 23. Alignment maintenance is accessible
  24. 24. Upper bearings are accessible
  25. 25. Alternate power options are available
  26. 26. 1.2 When to choose a submersible turbine
  27. 27. Extremely deep wells
  28. 28. Crooked wells
  29. 29. Sites with surface fooding problems
  30. 30. Highly noise-sensitive applications
  31. 31. Extreme surface site constraints
  32. 32. High risk of vandalism
  33. 33. Horizontal pipeline boosters
  34. 34. Part 2: Basic constraints
  35. 35. 2.1. Flow
  36. 36. Usually the one "given" in advance
  37. 37. Floor is usually set by demand
  38. 38. Ceiling is usually set by well capacity
  39. 39. 2.2. Head
  40. 40. Combination of static and dynamic factors
  41. 41. Static: Water level to pump discharge
  42. 42. Static factors: Drawdown at rated fow
  43. 43. Dynamic factors: Friction inside column
  44. 44. Wild card: Desired pressure at discharge head
  45. 45. Simple if a fxed discharge at a fxed elevation
  46. 46. More complex: Multiple destinations
  47. 47. More complex: Multiple fows
  48. 48. More complex: Varying pressures
  49. 49. 2.3. Physical shape and size
  50. 50. Size of hole available
  51. 51. Straightness of the drilled well
  52. 52. Larger diameters mean lower friction loss
  53. 53. Generally seek the most generous size that fts
  54. 54. Constraints at grade level: Footprint
  55. 55. Constraints at grade level: Overhead
  56. 56. 2.4. Laws of physics
  57. 57. Do the bowls ft?
  58. 58. Is minimum submergence achieved?
  59. 59. Is sufcient NPSH available?
  60. 60. Is the total head less than the bowl's limits?
  61. 61. Part 3: Other limitations
  62. 62. 3.1. Power
  63. 63. Hydraulic efciency
  64. 64. Drive (motor) efciency
  65. 65. Proper grounding is essential
  66. 66. Sizing for non-overloading power
  67. 67. Motor cooling: Above-grade
  68. 68. Motor cooling: Submersible
  69. 69. 3.2. Hydraulic thrust
  70. 70. Multiply total head by thrust factor
  71. 71. 3.3. Downthrust in three easy calculations
  72. 72. (a) Hydraulic thrust
  73. 73. (b) Weight per stage times number of stages
  74. 74. (c) Weight per foot of shaft times length
  75. 75. Downthrust = (a) + (b) + (c)
  76. 76. 3.4. Shaft elongation
  77. 77. Shaft & column stretch due to hydraulic thrust
  78. 78. Impellers must not rub against bowls
  79. 79. Net elongation = column - shaft elongation
  80. 80. Elongation is proportional to thrust
  81. 81. Elongation inversely proportional to shaft area
  82. 82. Bigger shafts mean less elongation
  83. 83. 4.1. Power source
  84. 84. Vertical turbine: Usually weather-protected
  85. 85. Premium efciency motors now dominant
  86. 86. Rate engines carefully for demand
  87. 87. 4.2. Discharge head
  88. 88. Determined by column, header, and driver size
  89. 89. Cast discharge heads usually start cheaper
  90. 90. High horsepowers require fabricated heads
  91. 91. VFD operations require fabricated heads
  92. 92. 4.3. Lubrication
  93. 93. Open lineshaft (usually)
  94. 94. Pumped fuid provides the lubrication
  95. 95. Closed lineshaft is usually lubricated by oil
  96. 96. Finally...
  97. 97. Certifcations NSF-61 for safe use in drinking water ISO 9001 for quality control Hydraulic Institute for performance standards
  98. 98. Materials No-lead is here to stay Sometimes stainless steel makes sense
  99. 99. Questions?  Thank you for your attention!  Brian Gongol  DJ Gongol & Associates  515-223-4144  brian@gongol.net  @djgongol on Facebook and Twitter  www.gongol.net or www.djgongol.com
  100. 100. Credits  Saturn from NASA  https://www.nasa.gov/jpl/cassini/pia18295  Bedrock aquifers from Iowa Geological Survey  https://www.iihr.uiowa.edu/igs/silurian-devonian-aquifer/  San Francisco real estate (retrieved Feb. 1, 2018):  https://www.trulia.com/real_estate/San_Francisco-California/market-trends/  Drawdown graph and photo of well in a parking lot from USGS  https://pubs.usgs.gov/sir/2010/5212/pdf/sir2010-5212.pdf  Many photos, drawings, and engineering data items were supplied courtesy of National Pump Co. for the purposes of this presentation  Other photos and illustrations are the original work of the author and all rights are reserved

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