PUMPING SYSTEMS BASICS. Waste Water Pump Types Effluent and De-watering (Sump pump)Sewage Pump (2”...
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Transcript of PUMPING SYSTEMS BASICS. Waste Water Pump Types Effluent and De-watering (Sump pump)Sewage Pump (2”...
PUMPING SYSTEMS BASICS
Waste Water Pump Types
Effluent and De-watering (Sump pump) Sewage Pump (2” solids)
Non-Clog (2 ½” solids)Grinder Pump
AUTOMATIC PUMPS
Mechanical Switch
Tethered Ball Float SwitchDiaphragm Switch
NON-AUTOMATIC PUMPS
Wide Angle Switches
PIGGY BACK FLOAT SWITCH
DOUBLE PIGGY BACK SWITCH
Control Switch
SIMPLEX SYSTEM
Simplex Control Panel
DUPLEX SYSTEM
Duplex Control Panel
BASINS
Polyethylene Basin
Fiberglass Basin
PUMP SIZINGTHREE BASIC QUESTIONS FOR SIZING:
1. HOW MUCH ( Demand)2. HOW HIGH ( Static Head)3. HOW FAR ( Friction Head)
Calculating System Demand( HOW MUCH)
POPULATION METHOD:Formula: ((NP x 100 gal/day/person x 4 )/24hrs/day )/60 min/hr. = GPM
NP = population served. Number 4 is the peak flow factor
Examples: 80 people in a sub-division.
((80 x 100 x 4)/24)/60 = 23 GPM.
FIXTURE COUNT METHOD:Each fixture in a building is given a “ unit weight”.The total “unit weight” of all the fixture in the building is referenced on a conversion graph and a gallons per
minute flow is determined.
Calculating System Demand
Static Head( How High)
Static Head
Pump
Discharge Line
Discharge Point
Static Head = Elevation Change
Friction Head( HOW FAR)
Pump
Discharge Line
Discharge Point
Friction head is determined by adding the total length of the discharge line (including fittings) then referencing a friction loss chart . Using the system demand flow and the size of the discharge pipe, the total head loss can be found.
TOTAL DYNAMIC HEAD = Static Head + Friction Head
Discharge Pipe SelectionMINIMUM FLOW VELOCITY: In order to keep solids
flowing in a horizontal pipe, a velocity of 2 ft. / sec. must be maintained.
Suspended Solids
Flow rates required to maintain 2 ft./sec:2” pipe = 21 gpm 3” pipe = 46 gpm 4”
pipe = 80 gpm
2 ft./sec flow
Pipe
Discharge Volume Exchange
Discharge LineSewer Main
Pump
To Find volume in Discharge line: Length of discharge ( ft.) X gal/ft. = Gal in Line
Liquid Volume in Pipe: 2” = .17 gal/ft.
3” = .36 gal/ft.
4” = .65 gal/ft.
Pump and System Curves
System Curve
Combined Pump and System
Curves
Basin Sizing & Selection
1. Physical Dimensions : Will it Fit ?
Discharge Volume Exchange
Discharge LineSewer Main
Pump
To Find volume in Discharge line:
Length of discharge ( ft.) X gal/ft. = Gal in Line
Liquid Volume in Pipe: 2” = .17 gal/ft.
3” = .36 gal/ft.
4” = .65 gal/ft.
There should be enough draw-down to change the volume in the discharge line every cycle.
Pump on
Pump offDraw down
Basin
Discharge Volume Exchange
Discharge LineSewer Main
Pump
To Find volume in Discharge line:
Length of discharge ( ft.) X gal/ft. = Gal in Line
Liquid Volume in Pipe: 2” = .17 gal/ft.
3” = .36 gal/ft.
4” = .65 gal/ft.
There should be enough draw-down to change the volume in the discharge line every cycle.
Pump on
Pump offDraw down
Basin
Basin Sizing CalculationsEXAMPLE: Commercial building with 50 gpm flow rate. Pump selected has a flow rate of 60
gpm. The pump height is 18” and the invert is 8”. The discharge line is 3” in diameter and 150 ft long.
Step 1. Invert Distance - 8”Step 2. Pump Height - 18”Step 3. Draw down ( largest of the following )
a. Max starts – (( 50 gpm x 60 min )/ 6) x .4 = 200 gal/cycle 200 gal / 4.4 gal per inch = 45”
b. Volume in discharge - .36 gal / ft x 150ft = 54 gal 54 gal / 4.4 gal per inch = 12”c. Pump run time : (60 gpm x 1 Min) / 4.4 gal per inch= 14
The total of all three critical dimensions is 71” The closest basin depth is 72”. Thus the suggested basin is 36 x 72. If this depth is too great for the application, then a wider basin can be used. This would result in a shallower basin.
Calculating Depth
• 36” diameter basin:
Pump
Floor level
Inlet pipe8”
18”
45” (Draw down)
Note: This would result in a complete change of volume and a run time of 3.5min
Invert
Residential Reality The preceding examples work well for commercial applications and for those
residential applications serving the whole house. The reality is that most residential sewage applications serve just one, seldom used bathroom. In these applications the usage is so small that the pump protecting guidelines do not have the same importance. In these applications, a 2” solids pump and an 18 x 30 poly basin work very well.
Related Topics
VENTS AND AIR ADMITTANCE VALVES
Water level
Potential confined air
Vent to atmosphere
Studor AAV
Liquid Inflow
Incoming liquid displaces air, which is released through the vent. AAV’s prevent this release, causing the system to “air lock”.
Questions• For Additional Information:
Chris [email protected](317) 670-9764