# PUMPING SYSTEMS BASICS

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PUMPING SYSTEMS BASICS

Effluent and De-watering (Sump pump)
Waste Water Pump Types Effluent and De-watering (Sump pump) Sewage Pump (2” solids) Non-Clog (2 ½” solids) Grinder Pump

AUTOMATIC PUMPS NON-AUTOMATIC PUMPS Mechanical Switch
Tethered Ball Float Switch Diaphragm 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

THREE BASIC QUESTIONS FOR SIZING:
PUMP SIZING THREE 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.

Calculating System Demand
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.

Static Head ( How High) Discharge Point Discharge Line

Friction Head ( HOW FAR) Discharge Point Discharge Line
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. Pump TOTAL DYNAMIC HEAD = Static Head + Friction Head

Discharge Pipe Selection
MINIMUM FLOW VELOCITY: In order to keep solids flowing in a horizontal pipe, a velocity of 2 ft. / sec. must be maintained. 2 ft./sec flow Pipe Suspended Solids Flow rates required to maintain 2 ft./sec: 2” pipe = 21 gpm 3” pipe = 46 gpm 4” pipe = 80 gpm

Discharge Volume Exchange
To Find volume in Discharge line: Length of discharge ( ft.) X gal/ft. = Gal in Line Sewer Main Discharge Line Liquid Volume in Pipe: 2” = .17 gal/ft. 3” = .36 gal/ft. 4” = .65 gal/ft. Pump

Pump and System Curves Combined Pump and System Curves System Curve

Basin Sizing & Selection
1. Physical Dimensions : Will it Fit ?

Discharge Volume Exchange
Liquid Volume in Pipe: 2” = .17 gal/ft. 3” = .36 gal/ft. 4” = .65 gal/ft. To Find volume in Discharge line: Length of discharge ( ft.) X gal/ft. = Gal in Line Basin Sewer Main Discharge Line Pump on Draw down Pump off Pump There should be enough draw-down to change the volume in the discharge line every cycle.

Discharge Volume Exchange
Liquid Volume in Pipe: 2” = .17 gal/ft. 3” = .36 gal/ft. 4” = .65 gal/ft. To Find volume in Discharge line: Length of discharge ( ft.) X gal/ft. = Gal in Line Basin Sewer Main Discharge Line Pump on Draw down Pump off Pump There should be enough draw-down to change the volume in the discharge line every cycle.

Basin Sizing Calculations
EXAMPLE: 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 ” 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 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: Floor level 8” Invert Inlet pipe
45” (Draw down) Pump Note: This would result in a complete change of volume and a run time of 3.5min 18”

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.