iSave 50

Summary

Product identification

• Product Name: iSave® Energy Recovery Device iSave 50 / iSave 70
• Function: Energy Recovery Devices (ERD) for Reverse Osmosis (RO) systems, designed to recycle energy from discharged brine from the membranes.
• Design: Consists of an isobaric pressure exchanger and a positive displacement vane pump combined into one compact unit. The vane pump principle enables a light and compact design, where flow is proportional to the number of revolutions (rpm) of the driving shaft, allowing for flow control via a Variable Frequency Drive (VFD).
• Fluid Compatibility: Designed for use with low viscosity and corrosive fluids such as seawater.
• Durability: All included parts are designed to provide long service life with constant high efficiency and minimum service required.
• Flow Characteristics: Produces a similar flow at a given speed regardless of discharge pressure, unlike centrifugal pumps.

Applications

• Containerized solutions for hotels and resorts on islands as well as coastal regions.
• Onboard systems for ships.
• Offshore platforms for the oil and gas industry.
• Municipal and private waterworks.

Operating limits

Pressure

• Max. differential pressure (HP out - HP in): 5 barg (72 psig)
• Min. pressure HP out (min. allowable working pressure): 40 barg (580 psig)
• Max. pressure HP out (Max. allowable working pressure, MAWP):
  • iSave 50: 83 barg (1200 psig)
  • iSave 70: 70 barg (1015 psig)
• Min. pressure on HP in, intermittent: 2 barg (29 psig) (acceptable for less than 10 minutes within a 6-hour period)
• Max. pressure LP in (MAWP): 5 barg (72 psig)
• Max. pressure LP in, peak: 10 barg (145 psig)
• Min. allowable working pressure LP in: 2 barg (29 psig)
• Max. differential pressure (LP in - LP out):
  • iSave 50: 0.53 barg (7.69 psig)
  • iSave 70: 0.79 barg (11.46 psig)
• Max. static test pressure (HP in and HP out): 108 barg (1566 psig)
• Max. static test pressure (LP in and LP out): 13 barg (189 psig)

Speed

• Min. speed:
  • iSave 50: 525 rpm
  • iSave 70: 625 rpm
• Max. speed:
  • iSave 50: 650 rpm
  • iSave 70: 875 rpm

Flow (HP out)

• Flow at min. speed, HP out:
  • iSave 50: 42 m³/h (184 gpm)
  • iSave 70: 50 m³/h (220 gpm)
• Flow at max. speed, HP out:
  • iSave 50: 52 m³/h (228 gpm)
  • iSave 70: 70 m³/h (308 gpm)
• Max. lubrication flow at 60 barg (871 psig): 25 l/min (6.6 gpm)
• Peak flow, LP in: 120 m³/h (528 gpm) (at system start-up, for up to 10 min, 150% of max. rated flow)
• Max. allowable working flow, LP in:
  • iSave 50: 57.2 m³/h (252 gpm)
  • iSave 70: 70 m³/h (308 gpm) (continuous operation with up to 10% over flush, with the limitation that the flow rate at LP inlet shall not exceed 70 m³/h)

Temperature

• Media temperature: 2-35 °C (36-95 °F)
• Ambient temperature: 0-50 °C (32-122 °F)
• Rated motor ambient temperature (with motor): 40 °C (104 °F)

Torque

• Max. allowable working torque (iSave without motor):
  • iSave 50: 170 Nm (125 lbf-ft)
  • iSave 70: 190 Nm (140 lbf-ft)
• Max. allowable working torque (iSave with IEC or NEMA motor):
  • iSave 50: 170 Nm (125 lbf-ft)
  • iSave 70: 177 Nm (130.5 lbf-ft)
• Max. starting torque (stick/slip): 180 Nm (132 lbf-ft)

Feed water

• Filtration requirements (nominal): 3 micron melt-blown depth filter with good end sealings. A second stage filter solution is recommended if there is a high risk of water by-pass.
• Salinity increase at membrane at 40% recovery rate at balanced flow: 2-3% (dependent on NaCl concentration)

Electrical

Efficiency

• Efficiency at max. speed at 60 barg (871 psig):
  • iSave 50: 93.7%
  • iSave 70: 92.4%

Motor Data (IEC Motor)

• Nominal speed: 985 rpm
• Rated current at 400V: 37 A
• Motor size: 18.5 kW (30.0 HP)
• Frame size: IEC 200 L
• Poles: 6
• Rated motor torque at nominal speed: 177 Nm (130.5 lbf-ft)
• Motor insulation: Class B
• Motor degrees of protection: IP 55

Motor Data (NEMA Motor)

• Nominal speed: 1180 rpm
• Rated current at 400V: 36.2 A
• Motor size: 22.5 kW (30.0 HP)
• Frame size: NEMA 324/6T
• Poles: 6
• Rated motor torque at nominal speed: 179 Nm (132 lbf-ft)
• Motor insulation: Class B
• Motor degrees of protection: IP 55

Mechanical / hydraulic

Dimensions and Connections

• Connections: 3” Victaulic connections.
• Mounting: The iSave 50 and iSave 70 can be mounted horizontally and vertically. When mounted vertically, the electric motor must be placed at the top of the iSave. The port orientation can be changed by the customer by rotating the combined iSave and bell housing around the center of the motor shaft.
• Footprint (with motor):
  • Vertical position: 0.44 m² (4.71 foot²)
  • Horizontal position: 0.76 m² (8.14 foot²)
• Detailed dimensions and connection diagrams are available in the official PDF.

Weight

• iSave without motor (dry): 164 kg (362 lb)
• iSave without motor (operation with water): 172 kg (379 lb)
• iSave with IEC motor (dry, vertical/horizontal): 441/463 kg (972/1021 lb)
• iSave with IEC motor (operation with water, vertical/horizontal): 470/471 kg (1036/1038 lb)
• iSave with NEMA motor (dry, vertical/horizontal): 484/506 kg (1067/1116 lb)
• iSave with NEMA motor (operation with water, vertical/horizontal): 513/535 kg (1131/1179 lb)

Materials of construction

• All critical parts of the iSave are made of high corrosion-resistant materials, specifically Super Duplex 1.4410/UNS 32750 or Duplex 1.4462/UNS 32803.

Noise

• Sound pressure level LPA 1 m:
  • iSave 50: 83 dB(A)
  • iSave 70: 86 dB(A)
• Noise levels are influenced by speed (higher rpm makes more fluid/structure-borne pulsations/vibrations), pressure (high pressure makes more noise), mounting (rigid mounting makes more noise), connections (pipes connected directly to the iSave make more noise than flexible hoses), and Variable Frequency Drives (VFDs) if settings are not correct.
• Recommendations include using high-pressure flexible hoses between hard piping and the iSave, or multiple connections with Victaulic clamps, and mounting horizontal units correctly on a frame with dampeners to minimize vibrations and noise.

Service & Maintenance

• Warranty: One year service-free operation, maximum 18 months from date of production, provided the iSave has been running according to Danfoss specifications.
• Operational Conditions of Concern: Increased wear and spare parts costs can result from insufficient filtration, insufficient bleeding and venting, running at speeds outside specifications, wrong direction of rotation, or insufficient flushing or periods of standstill with seawater inside the iSave.
• Maintenance: Periodic inspections are required, with yearly inspections recommended. Water quality should be considered when determining inspection frequency. A purpose-designed tool kit is recommended.
• Repair Assistance: Contact Danfoss High Pressure Pumps for assistance with irregular function of Danfoss RO components.

Accessories

• 3” Inlet hose kit - 2 m (79”) 6 barg (87 psig), Type: 3” Victaulic, style 77, Code no. 180Z0144
• 3” Outlet hose - 1 m (39.4”) 80 barg (1160 psig), Type: 3” Victaulic, style 77, Code no. 180Z0611
• 3” Outlet hose - 1.79 m (70.0”) 80 barg (1160 psig), Type: 3” Victaulic, style 77, Code no. 180Z0612
• Coupling iSave 50 - iSave 70, Type: Softex 55H7-32H7, Code no. 180Z4003
• Base plate horizontal, Type: IEC200/NEMA324TC, Code no. 180Z4007
• Base plate vertical, Type: IEC200/NEMA324TC, Code no. 180Z4004

Useful Documents

• Start and stop of the SWRO with iSave (180R9213)
• Membrane cleaning of the RO system with the iSave (180R9214)
• Parallel coupled APP and iSave (180R9354)
• Pipe connections (180R9367)
• Pressure safety valve in the SWRO system (180R9371)
• APP and iSave overload protection (180R9372)
• Review sheet P&ID (180R9370)
• Filtration (521B1009)

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Disclaimer: This summary is based on extracted text and may not include all figures, footnotes, or the latest revisions from the official OEM PDF datasheet. Contractual data must always match the specific OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror