Free Download Professional Resources for RO System Design
CAD drawings, P&IDs, calculation software, and white papers – all created to simplify RO design and ensure the correct selection of Rohre® high-pressure axial pumps.
61.7 psi | 4.25 bar
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Hydraulic Characteristic Formula
Formula (Metric): $$N_s = \frac{n \sqrt{Q}}{H^{0.75}}$$
Parameters: *
$n$: Pump Speed (RPM)
$Q$: Flow at Best Efficiency Point ($m^3/s$)
$H$: Head at Best Efficiency Point ($meters$)
Engineering Note: Specific speed is a dimensionless index used to select the correct pump impeller geometry (Radial, Mixed, or Axial flow) for a given duty point.
Conversion Logic
Formulas: * $cP = cSt \times \rho$ (Dynamic to Kinematic)
$cSt = \frac{cP}{\rho}$ (Kinematic to Dynamic)
Parameters: * $cP$: Dynamic Viscosity (Centipoise)
$cSt$: Kinematic Viscosity (Centistokes)
$\rho$: Fluid Density ($g/cm^3$)
Engineering Note: Viscosity is temperature-dependent. For high-salinity brine, the density ($\rho$) is significantly higher than pure water, which directly impacts the pump’s power requirement and hydraulic efficiency.
Calculation Logic & Formula
Formula: $Recovery (\%) = (\frac{Q_p}{Q_f}) \times 100$
Parameters: * $Q_p$: Permeate Flow Rate (Product Water)
$Q_f$: Feed Water Flow Rate (Total Inlet)
Engineering Note: In Seawater RO (SWRO) systems, the typical recovery rate ranges from 40% to 45%. Higher recovery increases the concentration of salts in the brine, requiring higher feed pressure from the pump.
Calculation Logic & Formula
Formula: $Rejection (\%) = [1 – (\frac{C_p}{C_f})] \times 100$
Parameters: * $C_p$: Permeate TDS or Conductivity
$C_f$: Feed TDS or Conductivity
Engineering Note: This value indicates the membrane’s efficiency in removing dissolved solids. Modern high-rejection membranes typically achieve $>99.5\%$ in standard seawater conditions.
Sizing Methodology
Formula: $V_{tank} = (V_{element} \times N) \times SF$
Parameters: * $V_{element}$: Volume of cleaning solution per membrane element (Standard: 40L for 8040 elements)
$N$: Total number of membrane elements in the system
$SF$: Safety Factor (typically 1.1 – 1.2 to account for pipe volume and pump suction margin)
Engineering Note: Ensuring an adequate volume is critical for maintaining stable chemical concentration and preventing pump cavitation during the CIP (Clean-In-Place) cycle.
EDI Feed Water Temperature Correction:
$$EC_{25} = \frac{EC_{T}}{1 + \alpha \cdot (T – 25)}$$
$EC_{25}$: Conductivity corrected to 25°C (Standard for EDI feed)
$EC_{T}$: Measured conductivity at actual temperature $T$
$T$: Actual water temperature (°C)
$\alpha$: Temperature compensation coefficient (typically 0.021 or 2.1% per °C for RO permeate)
Resource Categories
For engineers designing RO systems with Rohre® axial piston high-pressure pumps
CAD Drawings
- General Assembly for 3m³/h RO System (DWG)
- Equipment Layout for 45 m³/h RO System (DWG)
- Process Flow Diagram (PFD) for Two-Stage RO System (DWG)
- Process Flow Diagram (PFD) for 3×40 m³/h RO System (DWG)
- RO Process Flow Diagram (DWG)
- P&ID for 50m³/h RO System (DWG)
- RO Unit Drawing (DWG)
- RO Process Flow Diagram (PFD) (DWG)
- RO Fabrication Drawing (DWG)
- Detailed Piping Construction Drawing for RO Process (DWG)
- Single-Stage RO Unit Drawing – Network (DWG)
- P&ID for RO Process Flow (DWG)
- RO System Design Flow Diagrams
- RO Accessories
Calculation Software
- SDI Correction Formula for RO Feed Water(Excel)
- RO Cleaning Tank Calculation
- RO Calculation Sheet
- Calculation Formulas for Chemical Dosing in RO Systems
- RO Chemical Dosing Budgeting Software
- RO Mass Balance Calculation
- UF and RO Chemical Dosing Calculation
- Reverse Osmosis–EDI Calculation Sheet
- UF–RO Calculation
- RO–EDI Integrated Water Treatment Process Flow Chart
Expert Technical Support & Pump Selection
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