521B1116 DKCFN.PD.003.A1.02 10-2009

DATA SHEETEnergy Recovery Device

iSave 21-40

1. General information

The iSave 21-40 consists of an isobaric pressure exchanger (PE), a high pressure positive displacement booster pump (BP) and an electric motor.

The isobaric pressure exchangers are based on the technology used in the Danfoss APP pumps, and the high-pressure booster pumps are based on the vane principle enabling a very light and compact design. The design of iSave 21-40 ensures lubrication of the moving parts by the fluid itself.

All parts included in the iSave 21-40 are designed to provide long service life with a constant high efficiency and minimum service required.

The vane pumps are fixed displacement pumps in which the flow is proportional to the numbers of revolutions of the input shaft and the pump displacement – meaning flow control.

The electric motor provides speed control of both the pressure exchanger and the high-pressure booster pump by the same shaft – preventing over spin / over flushing.

A VFD controlling the speed of the iSave also provides fail/save communication to the service staff.

1: 2” victaulic connections2: Shaft3: Low pressure shaft seal4: Mounting flange (PE)5: Port Plate – Brine 6: Valve plate7: Connectors.8: End flange (PE)9: BP inlet port plate 10: Pin11: Vanes12: BP outlet port plate13 Internal coupling14: Adapter Flange15: Rotor 16: Stator17: BP port flange. 18: Outlet flange

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2. Benefits• Oneofthesmallestandlightestenergyrecoverydevicesonthemarket.• Fewcomponents.• Highefficiency.• Noneedforhigh-pressureflowmeters.• Noexpensivehigh-pressuremechanicalseal.• Noriskofoverspin/overflushing.• Easymodularservice• Allpartsofthedevicearemadeofhighcorrosionresistantmaterialsegsuper-duplex.

3. Technical dataCode number 180F7000 Available medio 2010

Energy Recovery Device iSave 21 iSave 40

Flow (1500 rpm1) ) 21 m3/hr (92.4 gpm) 40 m3/hr (176.1 gpm)

Geometric displacementcm3/rpm(in3/rpm)

265.8(16.2)

506.3(30.9)

Maximum high-pressure inlet flow 21 m3/hr (92.4 gpm) 40 m3/hr (176.1 gpm)

Maximum low-pressure inlet flow 33 m3/hr (92.4 gpm) 67 m3/hr (176.1 gpm)

Maximum high-pressure outlet 82.7 bar (1200 psig) 82.7 bar (1200 psig)

Maximum low-pressure outlet N/A N/A

Maximum high-pressure Inlet 82.7 bar (1200 psig) 82.7 bar (1200 psig)

Maximum low-pressure Inlet 10 bar (145 psig) 10 bar (145 psig)

Minimum high-pressure Inlet 10 bar (145 psig) 10 bar (145 psig)

Minimum high-pressure Inlet, intermittent 2) 3) 3 bar (43.5 psig) 3 bar (43.5 psig)

Minimum discharge pressure 1 bar (14.5 psig) 1 bar (14.5 psig)

Filtrationrequirements(Nominal 5) ) 3 µm pleeded 3 µm pleeded

Maximum speed 1500 rpm 1500 rpm

Maximum head of high-pressure booster pump 3 bar (43.5 psi) 3 bar (43.5 psi)

Maximum torque 1) 45Nm N/A

Power requirement at 60 bar, 1500 rpm and poster pressure of 4 bar

5.5kWh 11kWh

Electric motor 5.5kW 11kW

Weightincludingelectricmotor 90kg 162kg

1) Typical average flow at 60 bar and a booster pressure of 4 bar2) Minimum inlet high pressure can be 1 bar, if speed of iSave is maximum 750 rpm.3) Intermittent pressure is acceptable for less than 10 minutes per 6 hour.4) Starting torque on shaft can bee lowered by ramping up the speed from zero to maximum over a period of 20 seconds.5) Noiselevelisdependingsystemdesign.Thenoiselevelof87dBAcanbeobtainedby“prober”design.Pleasecontact Danfoss RO Sales organization.

PeakeffiencyincludingHighPressureBoosterPumpat60bar 93 % 93 %

MaxHighPressureDifferentialinthepressureexchanger @ 21 m3/hr @ 40 m3/hr

Max Low Pressure Differential in the pressure exchanger 0,7 bar (10,2 psi) @ 21 m3/hr 0,7 bar (10,2 psi) @ 40 m3/hr

Max lubrication flow 0,72 m3/hr (3.2 gpm) 0,8 m3/hr (3.5 gpm)

Max speed 1500 rpm 1500 rpm

Salinity Increase Membrane at 40% Recovery 2-3 % 2-3 %

TypicalNoiseLevel5) 87 dBA 87 dBA

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4. Flow at different rpmThe diagram shows that the flow can be changed by changing the rotation speed of the iSave. The flow/rpm ratio is constant andthe“desired”flowcanbeobtainedbychangingtherotationspeedtoacorrespondingvalue.Thus,therequiredrpmcanbedetermined as:

Desired flow × Rated rpm Required rpm = Rated flow

5. Temperature and corrosion

5.1 Operation: • Fluidtemperature: +3°Cto+50°C(+37.4°Fto122°F)-dependentontheNaClconcentration• Ambienttemperature: +3°Cto+50°C(+37.4°Fto122°F)

ThechartbelowillustratesthecorrosiveresistanceofdifferenttypesofstainlesssteelrelatedtoNaClconcentrationandtemperature.AllcriticalpartsoftheiSaveismadeofsuper-duplex1.4410/UNS32750orthelike.AlwaysflushtheiSavewithfreshwateratoperationstopinordertominimizetheriskofcrevicecorrosion.

5

10

15

20

25

30

35

40

500 600 700 800 900 1000 1100 1200 1300 1400 1500 rpm

m3/hr iSave21 iSave40

316L

904L / SAF 2205Duplex

SAF 2507Super duplex

80 º C

70

60

50

40

30

20

100

160 1600

1000

16000

10 000

160000

100 000 CI

-ppm

NaCIppm

Duplex

Super Duplex

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5.2 Storage: • Storagetemperature: -40°Cto+70°C(+40°Fto158°F)–providedthatthepumpisdrainedoffluidandstored

”plugged”.

Frost protection is required at temperatures below 2°C.DanfossrecommendstouseDowcalNfromDowChemicalCompanyor Chillsafe mono propylene glycol from Arco Chemical Company.

6. Noise level

The noise level from the iSave21 and iSave40 is typically 87 dB(A) at 1500 rpm at 60 bar and a booster pressure of 3 bar.Since the iSave is mounted on a bell housing and electrical motor, the noise level can only be determined for the complete unit (system).It is therefore important that the iSave unit is mounted correctly on a frame with dampers to minimize vibrations and noise.It is also strongly recommended to use high-pressure flexible hoses between the hard piping in the RO-plant and the iSave.

The noise level is influenced by:• ThespeedoftheiSave.Highspeedcreatesmorenoisethanlowrpm.• RigidmountingoftheiSavegeneratesmorenoisethanflexiblemounting• PipemountingdirecttotheiSaveincreasesthenoiselevelcomparedtoflexiblehoses.

7. FiltrationIt is important that the incoming water is filtered properly to ensure optimum service life. A true graded density melt-blown depth filter cartridge rated at 3 μm is therefore recommended.

Asthevariousfiltersonthemarketdiffergreatly,Danfossrecommendsusingcartridgeswithconsistent,reliableperformanceandhigh efficiency and where fibres are blown continuously onto a central support core. Danfoss does not recommend cartridges requiring any type of binders or resins.Filters can be purchased from Danfoss.

Pleaseconferwithchapter“ROsystemswithiSave”onhowtoplacefilterinsystems.

Formoreinformationontheimportanceofproperfiltration,pleaseconsultourpublication“Filtration”(codenumber521B1009),which also will provide you with an explanation of filtration definitions and a guidance on how to select the right filter.

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8. Dimensions 8.1 iSave 21

8.2 iSave 40

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8.3 Complete iSave 21 with electric motor

8.4 Complete iSave 40 with electric motor

Description iSave 21 iSave 40

Parallelkey,DIN6885.mm,(inch) 5 x 5 x 20 (0.20 x 0.20 x 0.78) 8 x 7 x 32 (0.44 x 0.31 x 2.76)

High-pressureconnections 2” Victaulic 1) 3” Victaulic 1)

Low-pressure connections 2” Victaulic 1) 3” Victaulic 1)

Mounting flange SAE A 2 100 A2

Bleeding connections G1/4“ G1/4“

A (mm) B (mm) C (mm) D (mm) E (mm) F (mm) Electric motor

iSave 21 216 132 315 265 968 140 IEC132S-4,5.5kW

iSave 40 254 160 415 330 N/A 210 IEC132MC-4,11kW

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9. Installation

Mounting The figure below illustrates how to mount the iSave and connect it to the electric motor

A: Flexible couplingB: Bell housingC: Motor shaft

TheiSave21-40mustbesupportedwithabracketinfront

If alternative mounting is required, please contact Danfoss RO Sales Organization for further informationTo ensure easy mounting of the flexible coupling without using tools, the tolerances must be dimensioned accordingly

Note: Any axial and radial load on the shaft must be avoided

10. RO system with iSave

1.Placeinletfilter(1)infrontoftheiSave(2).Pleaseconsultsection7,“Filtration”forguidanceonhowtoselecttherightfilter. Thoroughly clean pipes and flush system prior to start-up.

2. Place a monitoring pressure switch (4) set at min. inlet pressure between filter and pump inlet. The monitoring switch must stop the high-pressure pump (3) and iSave (2) at pressures lower than min. inlet pressure.

3. Dimension the piping to obtain minimum pressure loss (large flow, minimum pipe length, minimum number of bends/connections and fittings to prevent pressure loss and flow turbulence). Use flexible hoses to minimize vibrations and noise.

4. To balance the flow between high-pressure in and low-pressure in, place a variable area flow meter (5) on low- pressure inlet

5.Inordertoeliminatetheriskofdamageandcavitation,apositivepressureatthelow-pressureoutletisalwaystobemaintained at min. and max. outlet pressure. It is recommended to install monitoring pressure switch (6) in order to prevent high/low pressure

6. Install a VFD to control the speed of the iSave.

7. Install a pressure control valve (7) to control pressure in low-pressure out.

8. Install an air bleed valve (8) on the highest point of the high-pressure piping

For alternative PID setup, please contact Danfoss RO-Solutions sales organisation

min. 3 mm air space

A B C

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11. ServiceProvided that the iSave has been running according to Danfoss specifications on pre-filtration, pressure and rotation speed, Danfoss guarantees 8,000 hours service-free operation, however max. 18 months from date of production.After 8000 hours of operation, Danfoss recommends an inspection where any worn parts must be replaced.

TheiSaveismadeofduplex/superduplexmaterialswithfinecorrosionproperties.However,it is always required to flush the iSave when the system is shut down. See start/stop procedure

11.1 Periodic maintenance Withoperationbelowthecurveforsuperduplexinthefigureinsection5.1,nopartsareexpectedtobereplacedwithinthefirst8000 hours of operation.

11.2 RepairIn case of irregular funtion of the iSave, please contact the Danfoss RO Solutions Sales Organisation.