WORKSHEET - HOW TO DETERMINE RATE OF FLOW FROM THE MERLIN SYSTEM - NORTH AMERICAN
Enter Your Values
Inlet Water TDS (measured)
ppm
Inlet Water Temperature
°F
Inlet Pressure
psi
3/8-inch Tubing
feet long
Obstructions in Permeate Line
Elevation Difference Between Merlin and Faucet
feet
Post Filter?
Faucet?
Assigned Values
Pressure Drop per Obstruction
0.5 psi
Pressure Drop per Postfilter
3 psi
Pressure Drop in Elevation
0.43 psi per ft
(feet Faucet is above Merlin)
1.
Determine the Inlet TDS =
ppm
2.
Determine the Inlet Water Temperature =
°F
3.
Determine the Net Driving Pressure of the Merlin system
Net Driving Pressure = Inlet Pressure - System Pressure Drop
(Follow instructions below)
3A.
Calculate the Flow Rate Adjustment Factor
This factor will be used with Table 1 to adjust the TDS of Inlet Water from 750 ppm to ppm.
-0.0002 ( ppm) + 0.15 =
gpm
3B.
Calculate the Tubing Pressure Drop
Inlet Pressure
= psi
Water Temp
= °F
Use Table 1 to estimate flow rate, 750 ppm NaCl @ °F and psi =
gpm
Adjust Table data for actual TDS using the Flow Rate Adjustment Factor gpm
Tubing Flow Rate = gpm
+ gpm = gpm @ ppm NaCl
Use Figure 4 to determine the pressure drop for 1 ft. tubing = psi
Tubing Pressure Drop for ft = ft x psi =
psi
3C.
Calculate the Obstruction Pressure Drop
obstructions X (0.5 psi) =
psi
3D.
Calculate Elevation Pressure Drop
feet elevation X 0.43 psi/ft =
psi
3E.
Calculate Postfilter Pressure Drop
postfilter X 3 psi =
psi
3F.
Calculate Faucet Pressure Drop
psi - psi - psi - psi - psi = psi
Use Table 1 to estimate flow rate, 750 ppm NaCl @ °F and psi = gpm
Adjust Table Data for actual TDS using the Flow Rate Adjustment Factor gpm
gpm + gpm = gpm @ ppm NaCl
Use Figure 8 and the Inlet Flow Rate of gpm to estimate the Faucet Pressure Drop =
psi
3G.
Calculate the System Pressure Drop
(System Pressure Drop = Tubing PD + Obstruction PD + Elevation PD + Postfilter PD + Faucet PD
psi + psi + psi + psi + psi = psi
psi
3H.
Determine the Net Driving Pressure
(
Net Driving Pressure = Merlin Inlet Pressure - System Pressure Drop)
psi - psi =
psi
4.
Determine the Merlin Flow Rate
Use Table 1 to estimate flow rate, 750 ppm NaCl @ psi and °F = gpm
Adjust Table Data for actual TDS using the Flow Rate Adjustment Factor gpm
gpm + gpm = gpm
TOTAL MERLIN FLOW RATE = gpm
Actual results may vary. Membrane performance may vary ± 15%.
