1 / 27

Pumps and Lift Stations

Pumps and Lift Stations. Background. Fluid Moving Equipment. Fluids are moved through flow systems using pumps, fans, blowers, and compressors. Such devices increase the mechanical energy of the fluid. The additional energy can be used to increase. Velocity (flow rate) Pressure Elevation.

ping
Download Presentation

Pumps and Lift Stations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pumps and Lift Stations

  2. Background Fluid Moving Equipment Fluids are moved through flow systems using pumps, fans, blowers, and compressors. Such devices increase the mechanical energy of the fluid. The additional energy can be used to increase • Velocity (flow rate) • Pressure • Elevation

  3. Why are most water towers 130 feet high? Because a column of water 2.31 ft high exerts a pressure of 1 psi, and most city water systems operate at 50 to 60 psi

  4. destination source Static head Static Head Difference in height between source and destination Independent of flow Static head Flow

  5. Friction Head Resistance to flow in pipe and fittings Depends on size, pipes, pipe fittings, flow rate, nature of liquid Proportional to square of flow rate Friction head Flow

  6. Net Positive Suction Head The allowable limit to the suction head on a pump 33 - friction losses through the pipe, elbows, foot valves and other fittings on the suction side of the pump

  7. Power Requirement Example Determine the power required to pump 2000 gpm against a head of 14 ft, if the efficiency of the pump is 75% or 50%.

  8. Power Requirement Example Lower efficiency means bigger motor and electrical controls, higher operating costs

  9. Sump Sizing Example DC = 0.375” per day Area drained = 28 acres Lift (from tile outlet in sump to discharge pipe outlet) = 6 ft Length of discharge pipe = 25 ft Pump cycles per hour = 5 and 20. Determine suitable sump size

  10. Sump Sizing Example Storage Volume (ft3) = 2 x Q (gpm) n (cycles/hr) Area of a Circle = 3.14 x (Diameter)2 4.

  11. Design Flowrate Q = 18.9 x DC x A Q = 18.9 x 0.375 x 28 = 198.5 gpm Say use Q = 200 gpm Sump Volume Calculation (5 cycles/hr) Vol = 2 x Q / n Vol = 2 x 200 / 5 = 80 ft3

  12. Min Required Volume = 80 ft3 -Try 4 ft diameter well Area = 3.14 x 42 / 4 = 12.6 ft2 Storage Depth = 80 /12.6 = 6.35 ft Try 6 ft diameter well Area = p x 62 / 4 = 28.3 ft2 Storage Depth = 80 /28.3 = 2.83 ft

  13. AFFINITY LAWS Flowrate varies with rotational speed: Q1/Q2 = N1/N2 Head varies with rotational speed squared: H1/H2 = (N1/N2)2 Power varies with rotational speed cubed: P1/P2 = (N1/N2)3

  14. Affinity Laws Example A pump with an efficiency of 80%, connected to a diesel engine, pumps 200 gpm against a head of 12 ft. What is the power output of the engine? What will be the flow rate, head and power output if the motor speed is increased from 500 rpm to 600 rpm?

  15. Affinity Laws Example P =(200 x 12)/(3960 x 0.8) = 0.76 hp Q2 = 200 x (600/500) = 240 gpm H2 = 12 x (600/500)2 = 17.3 ft P2 = 0.76 x (600/500)3 = 1.3 hp

More Related