Data sheet

Data sheet

Energy Recovery Device

iSave 21-40

hpp.danfoss.com

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

Table of Contents Contents

1.

1.1

1.2

General information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

iSave 21 Plus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

iSave 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

2. Benefits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

3.

3.1

3.2

3.3

Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

iSave without motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

iSave with IEC motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

iSave with NEMA motor (can only be ordered through Danfoss US) . . . . . . . . . . . . . . . . . . . . . . .7

4. Flow at different rpm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

5. Corrosion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

5.1 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

6. Noise level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

7. Filtration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

8.

8.1

8.2

8.3 iSave drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Assembled iSave 21 Plus and iSave 40 without electric motor . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Assembled iSave 21 Plus and iSave 40 with IEC electric motor . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Assembled iSave 21 Plus and iSave 40 with NEMA motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

9. Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

10. RO systems with an iSave. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

11.

11.1

11.2

Performance curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Performance and torque curves iSave 21 Plus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Performance and torque curves iSave 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

I

12. Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

12.1 Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

12.2 Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

12.3 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

1. General information

iSave 21 Plus iSave 40

1. 2” Victaulic connections

2. Shaft

3. Low pressure shaft seal

4. Port flange

5. Port plate

6. Valve plate

7. Cylinder drum

8. Port flange

9. Port plate

10. Pins

11. Vanes

12. Port plate

13. Coupling

14. Adapter flange

15. Rotor

16. Stator

17. Port flange

18. Outlet flange

The iSave 21 Plus and iSave 40 consists of an isobaric pressure exchanger, a high-pressure positive displacement booster pump 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 pump principle enabling a very light and compact design. The design of iSave 21 Plus and iSave 40 ensures lubrication of the moving parts by the fluid itself.

All parts included in the iSave 21 Plus and iSave

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 number of revolutions of the driving shaft – enabling flow control.

The electric motor provides speed control of both the pressure exchanger and the high- pressure booster pump on the same shaft

– preventing overspin/overflushing.

The iSaves need a VFD that allows the motor to apply a constant torque from low speed to maximum speed.

The sectional drawings below illustrate the main components of the iSave 21 Plus and iSave 40, respectively

1.1 iSave 21 Plus

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

1.2 iSave 40

1. 3” Victaulic connections

2. Shaft

3. Low pressure shaft seal

4. Port flange

5. Port plate

6. Valve plate

7. Cylinder barrel

8. Port flange

9. Sealing plate

10. Pins

11. Vanes

12.Port plate

13. Coupling

14. Adapter flange

15. Rotor

16. Stator

17. Port plate

18. Outlet flange

2. Benefits

4

• One of the smallest and lightest energy recovery devices on the market

• Few components

• High efficiency

• No need for high-pressure flow meters

• No expensive high-pressure mechanical seal

• No risk of over spin/over flushing

• Easy modular service

• All parts of the device are made of high

corrosion-resistant materials e.g. Super Duplex

(HP)

High-pressure outlet

(LP)

Low-pressure inlet

(HP)

High-pressure inlet

(LP)

Low-pressure outlet

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

3. Technical data 3.1 iSave without motor

iSave size

Code number

Geometric displacement cm³/rev

In³/rev

Pressure

Differential pressure HP in - HP out max.

HP max. outlet pressure

HP min. inlet pressure

HP max. inlet pressure

HP inlet min. pressure, intermittent

2) 3)

LP inlet max. pressure

LP inlet max. pressure intermittent

LP outlet min. pressure

3)

LP differential LP in - out at HP max. flow

1)

Speed

Min. speed

Max. speed

Typical flow

HP outlet flow range 4) at max. differential pressure rpm rpm m³/h gpm

Lubrication flow at 60 barg (871 psig) max. m³/h gpm m³/h

LP inlet max. flow gpm

Torque

Torque at max. differential pressure operation

1)

Max. starting torque (stick/slip)

Media temperature

5)

Ambient temperature o F o C o F

Filtration requirements (nominal) 6)

Salinity increase at membrane at 40% recovery rate kg

Weight lb

Nm lbf-ft

Nm lbf-ft o

C

1)

Continuous torque above max. differential pressure will reduce the lifetime of the iSave.

2)

Pressure can reach this pressure level at start-up and permeate flush.

3)

Intermittent pressure is acceptable for less than 10

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

psig barg psig barg psig barg psig barg psig bar psi bar psi barg psig barg psig barg

iSave 21 Plus

180F7015

273

16.7

6-22

26-96

0.4

1.8

33

145

1200

3

44

5

72

10

145

1

14.5

0.9

13

5

72.5

83

1200

15

217

83

500

1500

49

36

50

37

2-40

36-104

0-50

32-104

3 micron melt-blow

2-3 %

47

103

minutes within a period of 6 hours.

4)

Typical average flow at 60 bar.

5) Dependent on NaCI concentation.

6)

Please see section 7. filtration.

iSave 40

180F7011

626

38.2

21-41

92-180.5

0.8

3.5

67

295

102

75

150

110

2-40

36-104

0-50

32-104

1200

3

44

5

72

10

145

1

14.5

1.2

17.5

5

72.5

83

1200

20

290

83

600

1200

123

271

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

3.2 iSave with IEC motor iSave

Code number horizontal

Code number vertical

Motor size IEC version IEC 400 V,

50 Hz 1)

Frame size kW

HP

IEC pole

Motor data

Nominal speed

Min. speed at 400 V

Max. speed at 400 V

Rated current at 400 V

Torque

Motor torque at norminal speed 3) 4)

Motor torque at min. speed

Motor ambient temperature, max.

Motor insulation

Motor degrees of protection

Sound pressure level max.

Weight

6)

3)

Footprint (horizontal/vertical) rpm rpm rpm

A

Nm lbf-ft

Nm lbf-ft o C o

F

Class

IP dB(A) kg lb m² foot²

A)

Differential pressure HP in - HP out max. is limited

to 3 bar [44 psi]

iSave 21 Plus

A)

iSave 21 Plus

180F7016

180F7016

5.5

7.5

132 S

4

180F7017

180F7017

7.5

10

132 M

4

iSave 40

180F7001 180F7004

180F7003 180F7005

11 15

15

160 L

6

20

180 L

6

1450

500

1500

11

B

55

78

105

36

26.5

27

20

40

104

231

0.31

3.34

1450

2)

500

1500

15.2

970

600

3) 1100

22

970

600

1200

30

B

55

79

116

49

36

36

27

40

104

5)

108

80

95

70

40

104

B

55

84

254

255

0.32

560

0.5/0.16

672

0.54/0.17

3.45

5.38/1.72

5.81/1.83

146

107.7

129

95

40

104

B

55

84

305

1) Three-phase-asynchronous-motor according to

DIN-IEC and VDE 0530 standards.

• Voltage and frequency according to IEC 38

• The motors are fitted with a rating plate in multi-tension: 380-420 V / 660-720 V, 50 Hz or

440-480 V, 60 Hz

• Tolerance ± 5% according to VDE 0530

• Standard coating according to IEC 60721-2-1

2) If voltage is below 400 V we recommend to use another size of electric motor.

Please contact Danfoss High Pressure Pumps for further information.

3) Torque load for iSave and motor see diagram on page 23 and 25.

4) Due to inertia and stick-slip friction of the iSave, the torque may exceed the maximum allowable operation torque for the iSave when it is taken into use and/ or speed is ramped up from zero to maximum. A VFD or a soft starter must be used for ramp up.

5) The starting torque must not exceed the values

stated under “Max. starting torque (stick/slip)”. The

VFD must be able to deliver 140% start torque. The

Danfoss VFD type FC 301 and FC 302 can be used.

For advice on VFD settings, please consult our

relevant guideline or contact Danfoss.

6) A-weighted sound pressure level at 1 meter from

the pump unit surfaces (reference box) acc. to EN

ISO 20361 section 6.2. The noise measurements are

performed acc. to EN ISO 3744:2010 on ERD with

motor (motor-pump unit) at max. pressure and

speed.

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

3.3 iSave with NEMA motor (can only be ordered through Danfoss US) iSave

Code number horizontal

Code number vertical

Motor size NEMA version

1)

High efficiency 460 V, 60 Hz

Frame size kW

HP

NEMA pole

Motor data

Nominal speed

Min. speed continuous at 400 V

Max. speed continuous at 400 V

Motor rated current 460 V

Torque rpm rpm rpm

A

Motor torque at norminal speed

3) 4)

Motor torque at min. speed

4)

Motor ambient temperature, max.

3,300 feet above sea level

Motor degrees of protection

Sound pressure level max.

6)

Weight

Footprint (horizontal/vertical)

Nm

(lbf-ft)

Nm

(lbf-ft) o C

( o

F)

IP dB(A) kg

(lb) m² foot²

A)

Differential pressure HP in - HP out max. is limited

to 3 bar [44 psi]

iSave 21 Plus

A)

iSave 21 Plus

180U0013

180U0013

7.5

10

215TC

4

180U0052

180U0052

11

15

254

4

2) 1760

500

1500

12.4

152

335

0.38

4.09

40

29.4

20

14.7

40

104

55

78

*)

Tested with IEC motor

1765

500

1500

18

206

454

0.45/0.16

4.85/1.72

59.7

44

31

23

40

104

55

78

*)

iSave 40

180U0012

180U0002

15

20

286TC

6

1175

600

1200

24.2

1)

Three-phase-asynchronous-motor according to

NEMA MG-1 and UL 1004-1 standards.

• Insulation class F, service factor 1.25.

• Fan-cooled TEFC (IC411). Voltage and frequency according to NEMA MG-1 part 12.

• The motors are fitted with a rating plate 230 /

460 V, 60 Hz.

• Plus or minus 10% of rated voltage, with rated frequency. Standard coating according to motor supplier specifications.

5)

The starting torque must not exceed the values

stated under “Max. starting torque (stick/slip)”. The

VFD must be able to deliver 140% start torque. The

Danfoss VFD type FC 301 and FC 302 can be used.

For advice on VFD settings, please consult our

relevant guideline or contact Danfoss.

6)

A-weighted sound pressure level at 1 meter from

the pump unit surfaces (reference box) acc. to EN

ISO 20361 section 6.2. The noise measurements are

performed acc. to EN ISO 3744:2010 on ERD with

motor (motor-pump unit) at max. pressure and

speed.

2)

Max. speed for iSave 21 is 1500 rpm.

3)

Torque load for iSave and motor see diagramme on

page 23 and 25.

4)

Due to inertia and stick-slip friction of the iSave, the

torque may exceed the maximum allowable

operation torque for the iSave when it is taken into

use and/ or speed is ramped up from zero to

maximum. A VFD or a soft starter must be used for

ramp up.

119

5)

88.2

95

70

40

104

55

84

324

715

0.65/0.23

7.0/2.48

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

4. Flow at different rpm

The diagram shows that the HP flow can be changed by changing the rotation speed of the iSave. The flow/rpm ratio is constant, the required flow is obtainable by changing the rotation speed to a required value.

For accurate data please use our selection tool which is available on our website: www.isave.danfoss.com

The iSave is delivered with a 3.1 performance certificate according to EN10204.

45

40

35

30

25

10

5

20

15

0

500 600 700 800

Flow at HP out vs. rpm

900 1000

rpm

1100 iSave 40

1200 iSave 21 Plus

1300 1400

198

176

154

132

110

1500

0

44

22

88

66

5. Corrosion

5.1 Operation

The chart below illustrates the corrosive resistance of different types of stainless steel related to NaCl concentration and temperature.

All critical parts of the iSave is made of

Super Duplex 1.4410/UNS 32 750 or Duplex

1.4462/UNS 32803.

Always flush the iSave with fresh water at operation stop in order to minimize the risk of crevice corrosion.

80 º

C

70

60

50

40

30

20

100

160

316L

1000

1600

Duplex

Super Duplex

10 000

16000

100 000

160000

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

6. Noise level

The noise level for the iSaves is measured at max. speed, a pressure of pressure of

(system).

5 bar.

80 barg and a booster

Since the iSave is mounted on a bell housing and electric motor, the noise level can only be determined for the complete unit

It is therefore important that a horizontal iSave unit is mounted correctly on a frame with dampeners to minimize vibrations and noise.

We recommend to mount a vertical iSave directly to the floor with bolts. It is also strongly recommended to use high-pressure flexible hoses between the hard piping in the RO-plant and the iSave or to use multiple connections with

Victaulic clamps.

Pressure:

• High pressure makes more noise than low

pressure.

Mounting:

• Rigid mounting makes more noise than flexible mounting due to structure-borne

vibrations.

Connections to iSave:

• Pipes connected directly to the iSave make more noise than flexible hoses due to

structure-borne vibrations.

• Variable frequency drives (VFD):

Motors regulated by VFDs can increase noise level if the VFD does not have the right settings.

The noise level is influenced by:

Speed:

• High rpm makes more fluid/structure-borne pulsations/vibrations than low rpm due to higher frequency.

Noise level (dB(A) measured for the iSave 21 Plus and 40 at different speed and system pressure.

Booster pressure 3 bar.

iSave 21 Plus

barg/psig rpm

500

1000

1500

20/290

60

69

77

60/870 80/1160

62

72

78

68

74

78

iSave 40

barg/psig rpm

800

1000

1200

30/435

73

76

78

60/870 80/1160

77

79

82

78

81

84

7. Filtration

It 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.

It is important with selection of a proper filter housing to ensure good cartridge end sealing.

If there is a high risk of water by-pass it is recommended to use a second stage filter solution.

As the various filters on the market differ greatly,

Danfoss High Pressure Pumps recommends using cartridges with consistent, reliable performance and high efficiency and where fibres are blown continuously onto a central support core. High Pressure Pumps does not recommend cartridges requiring any type of binders or resins.

Filters can be purchased from Danfoss

High Pressure Pumps. Please see section 10.0,

“RO systems with an iSave”, for installation of filter. For more information on the importance of proper filtration, please consult our publication

“Filtration” (code number 521B1009), which also will provide you with an explanation of filtration definitions and a guidance on how to select the right filter.

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

8. iSave drawings 8.1 Assembled iSave 21 Plus and iSave 40 without electric motor

iSave 21 Plus

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 40

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

8.2 Assembled iSave 21 Plus and iSave 40 with IEC electric motor

iSave 21 Plus, 5.5 kW, 4 pole, IEC motor

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 21 Plus, 7.5 kW, 4 pole, IEC motor

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 40 - horizontal, 11 kW, 6 pole, IEC motor

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 40 - horizontal, 15 kW, 6 pole, IEC motor

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 40 - vertical, 11 kW, 6 pole, IEC motor

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 40 - vertical, 15 kW, 6 pole, IEC motor

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

8.3 Assembled iSave 21 Plus and iSave 40 with NEMA motor

iSave 21 Plus, 10 HP, 4 pole, NEMA motor

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 21 Plus, 15 HP, 4 pole, NEMA motor

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 40 - horizontal, 20 HP, 6 pole, NEMA motor

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

iSave 40 - vertical, 20 HP, 6 pole, NEMA motor

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

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Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

9. Installation

Orientation

iSave 21 Plus and iSave 40 can be mounted horizontal and vertical. iSave 40 can be mounted horizontally and vertically - when mounted vertically, the electric motor must be placed at the top of the iSave.

The iSave 21 Plus baseplate can be used for both horizontal and vertical installations.

The iSave 40 has a base when installed vertical.

Mounting

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

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

min. 3 - 5 mm air space

A: Flexible coupling

B: Bell housing

C: Motor shaft

The iSave is connected to the electric motor by a bell housing and coupling.

If a horizontal iSave is delivered without base plate it is important to support the iSave and motor. The bell housing is not able to carry the weight of either the iSave or the motor when using horizontal mounting.

A B C

The iSave and motor must be supported without applying stress/overload to the bell housing.

If a horizontal iSave is delivered with a baseplate, a rigid mounting surface is required such as concrete foundation, optional base frame or a container with suitable steel substructure.

22

1: Motor

2: Flexible coupling

3: Bell housing

4: Base plate

5: Pressure exchanger

6: Booster pump

7: Port connection

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

10. RO systems with an iSave

P&ID setup

VFD

Media filter

1

4

PI

Filter

3 micron nominel PI

Filter

10 micron absolut

2

PI

PS

3

5

PI

PS

6

17

18

Flowmeter

12

LP in

7

Full flow cleaning

8

Fresh water permeate flush

*

HP out

11 iSave

HP in

10

PI

9

16

28

VFD

PS

13 14

PI

20

15

27

19

*

Second stage filter:

If recommended housing design and cartridges are not used, a second stage filter is required

Drain

CIP

Permeate

Explanation of P&ID setup

A. Place inlet filters on LP string in front of the iSave (11). Inlet filters assure proper water quality. High quality water extends the

service life of the whole system. It is impor

tant with selection of a proper filter housing

to ensure good cartridge end sealing. If there

is a high risk of water by-pass it is recom

mended to use a second stage filter solution.

Please consult section 7, “Filtration” for

guidance on how to select the right filter.

Thoroughly clean pipes and flush system prior to start-up.

B. Place a monitoring pressure switch set (3) at minimum inlet pressure between filter and pump inlet. The monitoring switch must stop the iSave (11) and the high-pressure pump (4) at pressures lower than minimum inlet pressure.

C. 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.

D. To balance the flow between high-pressure in and low-pressure in, place a variable area flow meter (12) on low-pressure inlet to the iSave.

E. In order to eliminate the risk of damage and cavitation, a positive pressure at the low- pressure outlet from the iSave is always to be maintained at minimum 1 barg (14.5 psig) and maximum 10 barg (145 psig). It is recommen-

ded to install monitoring pressure switch (13) in order to prevent high/low-pressure.

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

G. Install a pressure and flow control valve (15) to control pressure in low-pressure out.

H. Although the iSave 21 Plus automatically will bleed itself, there should be an air bleed valve

(8) installed on the highest point of the

high-pressure piping to ensure proper

bleeding of the RO system.

I. The pressure relief valve (6) protects the whole system against pressure overload and relieves the water if the pressure exceeds the maximum set pressure.

If the high-pressure pump is a positive displacement pump, the pump can built up a very high pressure that will exceed mechanical strength of the membrane housing, pipes and other accessories.

J. The pressure relief valve (19) protects the low-pressure pipes against pressure overload and relieves the water if the pressure exceeds the maximum allowable pressure.

For alternative P&ID setup, please contact

Danfoss High Pressure Pumps sales organisation.

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

23

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

11. Performance curves

11.1 Performance and torque curves iSave 21 Plus

1,4

1,2

1,0

0,8

0,6

0,4

1,8

22,0

1,6

0,2

0,0

5,0

30,8

7,0

39,6

Differential pressure vs. flow at LPin

48,4 57,2

gpm

66,0 74,8 83,7 92,5

9,0 11,0 13,0 15,0

m3/h

17,0 19,0 21,0

101,3 110,1

26,1

23,2

23,0

2,9

25,0

0,0

20,3

17,4

14,5

11,6

8,7

5,8

0,20

0,15

0,10

0,40

22,0

0,35

0,30

0,25

30,8

60 barg

30 barg

0,05

0,00

5,0 7,0

39,6

Lubrication flow vs. flow at HPout

48,4 57,2

gpm

66,0 74,8 83,7 92,5

9,0 11,0 13,0 15,0

m3/h

17,0 19,0 21,0

101,3 110,1

1,76

1,54

1,32

1,10

23,0

0,88

0,66

0,44

0,22

25,0

0,00

24 521B1464 | DKCFN.PD.003.3B.02 | 2018.01

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

25

20

15

10

5

0

400

40

35

30

50

45

500

Torque for iSave 21 and motor at 60 barg system pressure

600 700 800 900 1000

rpm

1100 1200 1300 1400 1500 1600

47,9

44,3

40,6

36,9

33,2

29,5

25,8

22,1

3,7

1700

0,0

18,4

14,8

11,1

7,4

62,7

59,0

55,3

51,6

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

25

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

11.2 Performance and torque curves iSave 40

Differential pressure, low pressure bar

1.40

1.20

1.00

0.80

0.60

0.40

0.20

0.00

20.0 22.0

100

24.0

140

26.0 28.0 30.0 32.0

180

psi

20

15

10

5

34.0 36.0 38.0 40.0 42.0 44.0

m

3

/h

Lubrication flow m

3

/h

1.00

0.90

0.80

60 barg

0.70

0.60

0.50

0.40

0.30

30 barg

0.20

0.10

0.00

20 22 24 26 28 30 32

34 36 38

gpm

3

1.5

40 42 44

m

3

/h

26 521B1464 | DKCFN.PD.003.3B.02 | 2018.01

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

90

80

70

60

50

40

30

20

60

0

Nm

150

140

130

120

110

100

65

0

X

70

0

Torque for iSave 40 motor at 60 barg system pressure

75

0

80

0

85

0

X

90

0

95

0

5 bar

X

72.5 psi

4 bar

58 psi

3 bar

43.5 psi

2 bar

29 psi

1 bar

14.5 psi

X

10

00

10

50

11

00

11

50

lbf ft

110.63

103.26

95.89

88.50

81.13

73.75

66.38

59.00

51.63

44.25

36.88

29.50

22.13

12

00

rpm

Important:

The marked area at 1100-1200 rpm shows the operation area which cannot be reached with a 11 kW motor at 400 voltage supply. A 15 kW is needed if max rpm (1100-1200) and max differential pressure (4 to 5 bar) is required.

Max motor torque for 15 kW, IEC180L-6, 50 Hz, 400 V

Max motor torque for 20 HP, NEMA286TC-6, 60 Hz, 460 V

X Max motor torque for 11 kW, IEC160L-6, 50 Hz, 400 V

Max motor torque for 11 kW, IEC160L-6, 60 Hz, 480 V

The straight pressure lines (1 to 5 bar) show the needed shaft torque for the iSave at different pressures.

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

27

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

12. Service

12.1 Warranty

The Danfoss iSave is designed for long operation, low maintenance and reduced lifecycle costs.

Provided that the iSave has been running according to the Danfoss specifications, Danfoss guarantees 8,000 hours service-free operation, however, max. 18 months from date of production.

The life of an iSave may be greatly shortened if

Danfoss recommendations concerning system design are not followed.

Standstill

The iSave is made of Duplex or Super Duplex materials with excellent corrosion resistance.

However, it is always required to flush the iSave when the system is shut down.

12.2 Maintenance

In our experience, poor filtration is the number one cause of iSave damage. Danfoss recommends an periodic inspection where worn parts, if any, must be replaced. This is done in order to to prevent a potential breakdown of the iSave.

12.3 Repair

In case of irregular function of the iSave, please contact Danfoss High Pressure Pumps.

28 521B1464 | DKCFN.PD.003.3B.02 | 2018.01

Data sheet | Energy Recovery Device | iSave 21 Plus and iSave 40

521B1464 | DKCFN.PD.003.3B.02 | 2018.01

29

Danfoss A/S

High Pressure Pumps

DK-6430 Nordborg

Denmark

Danfoss can accept no responsibility for possible errors in catalogues, brochures and other printed material. Danfoss reserves the right to alter its products without notice.

This also applies to products already on order provided that such alterations can be made without subsequential changes being necessary in specifications already agreed.

All trademarks in this material are property of the respective companies. Danfoss and the Danfoss logotype are trademarks of Danfoss A/S. All rights reserved.

© Danfoss | DCS (im) | 2018.01

521B1464 | DKCFN.PD.003.3B.02

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