Danfoss iSave 21 Plus Operating guide

Operating guide

Energy Recovery Device

iSave 21 Plus

Installation, Operation and

Maintenance Manual

hpp.danfoss.com

Operating guide | iSave 21 Plus

Document information and copyright

Installation, Operation and Maintenance Manual.

Original operating manual document.

Danfoss can accept no responsibility for possible errors in the manual and instructions. 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 rights reserved. Contents provided herein must neither be distributed, copied, reproduced, edited or processed for any other purpose, nor otherwise translated or published without Danfoss’ express written consent.

Validity

This manual is valid for iSave 21 Plus

Code no.	Serial no.
180F7015	XXXXXX02-XXX
180F7016	XXXXXX02-XXX
180F7017	XXXXXX02-XXX
180F7018	XXXXXX02-XXX

PUMP
Type	iSave 21 Plus ERD
Code no.	180BXXXX

Serial no. XXXXXX02-XXX

MADE IN DENMARK

Danfoss A/S, 6430 Nordborg, Denmark

The serial number is referring to the Serial no. on the product label. The digits shown (02) indicate the version number of the pump.

This document is only valid for ERD version 2 and upwards.

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Table of Contents
2	Introduction			6
	2.1	General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	.	. 6
	2.2	Target group		6
	2.3	Symbols		6
	2.4	Manufacturer and customer service address . . . . . . . . . . . . . .	.	. 7
	2.5	Country specific information . . . . . . . . . . . . . . . . . . . . .	.	7
	2.5.1	United Kingdom . . . . . . . . . . . . . . . . . . . . . . . . . .	.	. 7
	2.6	Additional technical documents . . . . . . . . . . . . . . . . . . . .	.	7
3	Safety			8
	3.1	General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	.	. 8
	3.2	Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . . .	.	9
	3.3	Application range . . . . . . . . . . . . . . . . . . . . . . . . . .	.	9
	3.4	Preferred system design . . . . . . . . . . . . . . . . . . . . . . .	.	9
4	Arrival inspection, handling and storage . . . . . . . . . . . . . . . . . .		.10
	4.1	Arrival inspection		10
	4.2	Return to the supplier		10
	4.3	Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	.10
	4.3.1	Centre of mass . . . . . . . . . . . . . . . . . . . . . . . . . . .	.	11
	4.4	Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	.	12
	4.5	Outdoor storage . . . . . . . . . . . . . . . . . . . . . . . . . .	.	12
5	Technical data and design review			13
	5.1	Design details		13
	5.2	Sound level of the iSave . . . . . . . . . . . . . . . . . . . . . . .	.	13
	5.3	Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. 14
	5.4	Temperature and corrosion . . . . . . . . . . . . . . . . . . . . . .	. 14
	5.5	Dimensions and weights . . . . . . . . . . . . . . . . . . . . . . .	.	14
	5.6	Electrical motor data . . . . . . . . . . . . . . . . . . . . . . . .	.	14
	5.7	How does the iSave work? . . . . . . . . . . . . . . . . . . . . . .	.	15
	5.7.1	Pressure excharger function		15
	5.7.2	Booster pump		16
	5.7.3	Lubrication flow . . . . . . . . . . . . . . . . . . . . . . . . . .	.	16
	5.7.4	Mixing		16
	5.7.5	How does the iSave work in an RO system? . . . . . . . . . . . . . . .	.	16
	5.8	Seawater quality . . . . . . . . . . . . . . . . . . . . . . . . . .	.	17
	5.8.1 Pre-filtration			17
	5.8.2 Air bubbles			18
	5.8.3 Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		.	18
	5.9	Initial start up and flushing . . . . . . . . . . . . . . . . . . . . . .	. 18
	5.10	Initial start up and settings of safety equipment . . . . . . . . . . . . . . . . . . .	. . 18
	5.11	Flushing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. 19
	5.12	CIP of Membrane cleaning		19
	5.13	High pressure remains after shutdown . . . . . . . . . . . . . . . . .	.	19
	5.14	Over-pressurisation caused by low pressure isolation		20
	5.15	Over-pressurisation caused by the high pressure pump . . . . . . . . . .	.20
	5.16	Preferred system design and P&ID		21

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6	On-site installation . . . . . . . . . . . . . . . . . . . . . . . .		. .	.	.	22
	6.1	General				22
	6.2	Installation and alignment . . . . . . . . . . . . . . . . . .	. .	. .		.22
	6.3	Orientation . . . . . . . . . . . . . . . . . . . . . . . . .	. .	.	.	22
	6.4	Piping and joints				23
	6.5	Flexible couplings and flexible hoses				24
	6.6	Mounting of coupling . . . . . . . . . . . . . . . . . . . .	. .	. .		.24
	6.7	Mounting of bell housing on iSave . . . . . . . . . . . . . . .	. .	.	.	24
	6.8	Accessibility				24
	6.9	Drives				25
	6.9.1	Electric motor				25
	6.9.2 Speed control . . . . . . . . . . . . . . . . . . . . . . . .		. .	. .		.25
	6.9.3 Starting torque on the iSave/ramping the electric motor . . . . . .		. .	.	.	25
	6.9.4 Torque overloads protection on the iSave					25
7	Commissioning, start-up and shutdown					26
	7.1	Safety regulations . . . . . . . . . . . . . . . . . . . . . .	. .	. .		.26
	7.2	Support . . . . . . . . . . . . . . . . . . . . . . . . . .	. .	. .		.26
	7.3	Commisioning . . . . . . . . . . . . . . . . . . . . . . . .	. .	.	.	26
8	Service/Maintenance					27
	8.1	Safety regulations . . . . . . . . . . . . . . . . . . . . . .	. .	. .		.27
	8.2	Support . . . . . . . . . . . . . . . . . . . . . . . . . .	. .	. .		.27
	8.3	Maintenance schedule . . . . . . . . . . . . . . . . . . . .	. .	. .		.27
	8.4	Tool used . . . . . . . . . . . . . . . . . . . . . . . . . .	. .	.	.	28
9	Trouble-shooting					29
	9.1	Safety regulations . . . . . . . . . . . . . . . . . . . . . .	. .	. .		.29
10	Appendix					30
	10.1	Start and stop procedures (180R9213)				31
	10.2	Membrane cleaning of the RO system with iSave unit (180R9214) . .	. .	. .		.37
	10.3	Data sheet iSave 21 Plus - iSave 40 (521B1464) . . . . . . . . . .	. .	. .		.43
	10.4	iSave part list (521B1459) . . . . . . . . . . . . . . . . . . . .	. .	.	.	73
	10.5	Hose assembly and installation (180R9434) . . . . . . . . . . . .	. .	.	.	83
	10.6	Operatingand maintenance instruction, electric motor (180R9230) .	. .	.	.	91

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2. Introduction	2.1 General
	iSave is manufactured by Danfoss A/S, and
	is sold and marketed by a net of authorised
	distributors world wide.
	This manual contains the necessary instruc-
	tions for the installation, operation and
	service of the iSave.
	All personnel who are responsible for
	the operation and maintenance of the iSave
	unit must read and fully understand these
	instructions, especially the section “Safety”
	before:
	• Transporting of the iSave unit.
	• Lifting the unit.
	• Installing the iSave unit on a frame.
	• Connecting the iSave unit to the fluid
	system.
	• Connecting the electrical motor and
	instrumentation.
	• Commissioning the unit.
	• Servicing the iSave unit, mechanics and
	electrics.
	• Decommissioning the iSave unit.
	Ensure that these instructions are
	always readily available to all personnel
	concerned.
	2.2 Target group
	This manual is intended for use by
	personnel with qualified training and
	experience in the operation and
	maintenance of a Sea Water Reverse
	Osmosis (SWRO) or Brackish Water Reverse
	Osmosis (BWRO) system.

2.3 Symbols

NB! Indicates something to be noted by the reader.

Indicates a situation which will or couldresult in damage to the iSave and its function.

Indicates a situation which will or could result in personal injury and/or damage to the iSave.

Electrical hazard. Indicates a high-voltage warning

Safety glasses required

Hearing protection required

Safety shoes required

Safety helmet required

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2.4 Manufacturer and customer service	2.5 Country specific information
address	1.4.1 United Kingdom
Danfoss A/S
DK-6430 Nordborg,	UK importer:
Denmark	Danfoss Ltd.
Telephone: [phone]	22 Wycombe End
Email: [e-mail]	HP9 1NB Beaconsfield
Home page: hpp.danfoss.com	United Kingdom
2.6 Additional technical documents
Document name	Content
Datasheet	Description of the technical data and
	dimensions of the iSave
iSave parts list	Sectional drawings, parts list and spare part
	numbers.
Instruction:	Description of how to start and stop the
start and stop of the SWRO with iSave unit	iSave in the preferred RO system set-up.
Instruction:	Description of how to clean the membranes
Membrane cleaning of RO system with	in the preferred RO system set-up.
iSave unit
Instruction:	Guideline for Hose assembly and
Hose assembly and installation	installation
Operating and maintenance instructions,	Operating and maintenance instructions for
electric motor	the standard electric motor, delivered from
	Danfoss.
See also appendix 10

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3. Safety

Electrical hazard

3.1 General	• Improper installation can cause fatal
The iSave must not be used for other	injuries.
purposes than those recommended and	• The iSave must not operate outside
specified without first consulting your local	the application range.
iSave distributor.	• During the initial start-up, slowly raise
	the pressure of the system and adjust
This manual must be read and completely	the over-pressure protection
understood by the responsible specialist	equipment for proper limit settings.
personnel prior to installation and commis-	• Make sure that the pressure is
sioning.	released from the iSave before the
Use of this manual does not relieve opera-	iSave is disconnected from any pipe
tion and maintenance personnel of the	or hose connections in the iSave.
responsibility of applying normal good	• Make sure that the iSave can be
judgment in the operation and care of this	drained without injuring anyone and
product and its components.	without contaminating nearby
	equipment or the environment.
This manual must be available to all person-	• Before intervening in the
nel concerned at the site at all time.	iSave/system, the power must be shut
	off and the starting device must be
An iSave must always be installed and used	locked. When intervening in the iSave
in accordance with existing national and lo-	unit, follow the instructions for
cal sanitary and safety regulations and laws.	Service/Maintenance, chapter 8.
It is the responsibility of the safety officer or	• A failure to follow the instructions can
the chief operator to assure compliance with	result in personal injury and/or
all local regulations that are not taken into	damage to the iSave. It will also
account in this manual.	invalidate the warranty.
The iSave is a rotating machine that typically	• The iSave must never run dry. Dry
operates at high pressure.	running produces heat and will cause
	damage to internal parts.
	• If the iSave does not function
Always wear suitable safety and lifting	satisfactorily, contact your local iSave
equipment when handling the iSave.	distributor.
• Bolt the iSave properly to the base	NB! Use of this manual does not relieve
before start-up to avoid personal	operation and maintenance personnel
injury and/or damage to the iSave.	of the responsibility of applying normal
• The pipe connections to the iSave	good judgment in the operation and
must be stress-free mounted, securely	care of this product.
fastened to the iSave and well
supported. Improper installation will
or could result in personal injury
and/or damage to the iSave.

•Proper installation and care of shutdown devices and over-pressure protection equipment is essential.

•All electrical installation work must be carried out by authorised personnel in accordance with EN60204-1 and/or local regulations.

•Install a lockable circuit breaker to avoid inadvertent starting. Protect th motor and other electrical equipment from overloads with suitable equipment.

•The electric motors must be supplied with adequate cooling ventilation.

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3.2 Intended use

The iSave is designed for use as energy recovery device in Sea Water Reverse Osmosis (SWRO) or Brackish Water Reverse Osmosis (BWRO) system.

The iSave must not be used for other purposes than recommended and quoted for without consulting your local iSave distributor.

3.3 Application range

For application range see data sheet 521B1464 available in appendix 10.3.

Applications not suitable for the iSave can cause damages to the iSave unit, with risk of personal injury.

3.4 Preferred system design

Danfoss recommends building systems with a high degree of safety. The P&ID in chapter 5.16 shows the Danfoss preferred system design.

•It is always the system builders’ responsibility that the system design does not cause any form of hazard and are adapted to local regulations.

•Proper installation and care of shutdown devices and over-pressure protectio equipment is essential.

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4. Arrival inspection,	4.1 Arrival inspection
handling and storage	The iSave is packed in a wood container with
	plugs in the port connections to protect the
	unit from damage during transport.
	Remove all packing materials immediately
	after delivery. Immediately check the
	shipment for damage on arrival and make
	sure that the name plate/type designation is
	in accordance with the packing slip and your
	order.
	In case of damage and/or missing parts, a
	report should be drawn up and presented
	to the carrier at once.
	The identification label on the iSave states
	the specific type, the serial number and the
	code number of the iSave; see fig. below.
	The last three digits of the Serial No. indicate
	the week and year of production.

4.3 Handling

•Personnel involved in lifting and transportation of the equipment must be trained in proper handling and safety procedures.

•Observe the local regulations regarding lifting.

•Use suitable, permitted lifting equipment.

•The iSave (set) could slip the lifting arrangement.

•Be aware of individuals located in the operation area while lifting the component.

PUMP

Type	iSave 21 Plus ERD
Code no.	180BXXXX

Serial no. XXXXXX02-XXX

MADE IN DENMARK

Danfoss A/S, 6430 Nordborg, Denmark

4.2 Return to the supplier

Flush the iSave with clean water. Drain the iSave and plug the port connections with a cap/cover.

Pack the iSave into a suitable container and make sure that it is suitably fastened to the container.

Please contact your local authorised distributor or:

Danfoss A/S DK-6430 Nordborg, Denmark

Telephone: [phone]

Fax: [phone]

Email: [e-mail] Homepage: hpp.danfoss.com

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Check the mass (weight) of the iSave unit. All parts weighing more than 20 kg must be lifted using lifting slings and suitable lifting

devices, e.g. an overhead crane or industrial truck. All iSave units weight more than

20 kg.

Once the lifting is done the lifting eye must be removed from the pump.

Secure lifting slings around the part of the iSave and the back of the electric motor. Make sure that the load is balanced before attempting the lift.

Never lift the iSave unit with only one			Never lift the iSave in the bell housing.
fastening point.
Incorrect lifting can result in personally			Incorrect lifting can result in personally
injury and/or damage to the unit.			injury and/or damage to the unit.

4.3.1 Centre of mass

604

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4.4 Storage

Each iSave is tested before shipment and therefore holds water.

Storage temperature: 1 °C to +70 °C (33 °F to 158 °F) – provided that the pump is drained of fluid and stored “plugged”.

Frost protection is required at temperatures below 1°C. Danfoss recommends using DOWFROST from DOW Chemical Company

or Chillsafe mono propylene glycol from Arco Chemical Company.

If the iSave is protected against frost, the storage temperature can be: -40 °C to +70 °C (-40 °F to 158 °F)

•The iSave is NOT delivered frost-protected from the factory.

•Only remove caps from the openings of the iSave at the time of installation.

4.5 Outdoor Storage

For outdoor storage cover the iSave (set) with waterproof material.

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5. Technical data and	5.1 Design details
design review

11

10

9

8

5

6

7

6

5

1

12

17

12

4

1

2

3

18

15

16	14	1	13	1
1: 2” Victaulic connections			7: Cylinder drum	13: Coupling
2: Shaft			8: Port flange	14: Adapter flange
3: Low pressure shaft seal			9: Port plate	15: Rotor
4: Port flange			10: Pins	16: Stator
5: Port plate			11: Vanes	17: Port flange
6: Valve plate			12: Port plate	18: Outlet flange

5.2 Sound level of the iSave

The noise level from the iSave including the electrical motor is 78 dB (A). Measurements according to EN ISO 20361. The test is made under following conditions:

1.iSave and electrical motor mounted on Danfoss base plate.

2.Baseplate is isolated from concrete ground by rubber vibration dampers.

3.Flexible hoses are used on high pressure and low pressure sides of the iSave.

4.Rotation speed 1,500 rpm

5.System pressure 60 barg and a booster pressure of 3 barg.

Influences

Since the iSave is mounted on a base plate and connected to the electromotor by a bell housing, 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 minimise 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. See “hose assembly and installation” in appendix 10.6. Alternative use multiple flexible Victaulic® couplings on the hard piping.

The noise level is influenced by:

•The speed of the iSave. High speed creates more noise than low speed.

•Rigid mounting of the iSave baseplate generates more noise than flexible mounting

•Pipe mounting directly to the iSave increases the noise level compared to flexible hoses.

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5.3 Materials

All critical parts of the iSave are made of super-duplex 1.4410/UN S32750 or the like. Non-critical parts that are not in contact with sea water are made of AISI 316.

The shaft to the electrical motor is sealed by a standardised mechanical seal.

For a detailed material/part overview see appendix

In order to minimise the risk of crevice corrosion, always flush the iSave according to the specified start/stop procedure.

5.4 Temperature and corrosion

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

Depending on the NaCl concentration, the fluid temperature must be between: +2 °C to +50 °C (+35.6 °F to 122 °F).

5.5 Dimensions and weights

For dimensions and weights please refer to the iSave datasheet. See appendix 10.3

5.6 Electrical motor data

See datasheet in appendix 10.3 and “Operating and Maintenance instructions, electric motor” in appendix 10.6

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5.7 How does the iSave work?

Figure 5.1 shows a section view of the iSave

The iSave consists of a rotating isobargic pressure exchanger and a positive displacement pump, also called booster pump. The rotation speed of the pressure exchanger and the pump is exactly the same, as they are driven by the same electric motor.

5.7.1 Pressure exchanger function:

The pressure exchanger consists of two port plates, one at the concentrate side and one at the seawater side. In between there is a rotor with several ducts that connect the concentrate side with the seawater side. The pressure exchanger transfers pressure from the high-pressure (HP) concentrate (HP in) to the low-pressure (LP) seawater coming from low-pressure feed pump (LP in).

To separate the HP side from the LP side there is a sealing zone on both port plates. A single duct in the rotor is either on the HP side, or on the LP side or in the sealing zone. A single duct is never in contact with more than one zone at the time. When the rotor rotates a duct will go from the LP zone over the first sealing zone into the HP zone, and hereafter from the HP zone over the second sealing zone and back to the LP zone.

The flow through the HP side of the iSave is forced and controlled by the booster pump.

When the high-pressure concentrate is flowing into the iSave it pressurizes the sea water in the duct coming from “LP in”. The pressurized seawater is then pumped out of “HP out”. Just before the HP concentrate in the duct comes to the seawater port plate, the duct goes into the sealing zone and the flow in the duct stops. When the duct goes into the LP zone the concentrate water is de-pressurized. The (LP) seawater coming from the LP feed pump (LP in) forces the LP concentrate out of “LP out”.

This pressure exchange process is repeated for each duct with every rotation of the rotor, and the ducts are thus continuously filling and discharging. The flow on the HP side and LP side of the iSave is nearly constant over time.

There is no physical barrier in the ducts between the concentrate and seawater. This means that there will be a small amount of mixing between the two liquids.

Fig. 5.1.		HP-in

HP-out			Concentrate
			side

Seawater side

LP-in				LP-out

NB!	When the iSave is rotating the water always
	flows respectively from LP-in to HP-out,
	AND from HP-in to LP-out. However, if the
	feed flow into LP-in is higher than the flow

into HP-in, some of the LP feed flow will flow directly to LP-out.

When the iSave is not rotating the seawater can only run directly from LP-in to LP-out.

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5.7.2 Booster pump

The booster pump is a positive displacement pump, which means that the flow is controlled by the speed of the electric motor; e.g. if the rotation speed

of the electric motor is raised by 10%, the flow will be 10% higher and vice versa. The required rpm can be calculated based on the “rated flow” of the particular iSave. See datasheet in appendix 10.3.

At low speeds you may hear some minor clicking sounds from the pump. This is normal and is caused by the pins in the vane pump.

5.7.3 Lubrication flow

To lubricate the moving parts in the pressure exchanger there is a well defined leak between the port plates and the rotor, as well as in the high pressure bearing between the pressure exchanger and the booster pump. This leak is typically called “lubricating flow”. The leaks go from the high pressure side to the low pressure side of the pressure exchanger, and from the booster pump to the low pressure side of the pressure exchanger.

5.7.4 Mixing

There is no physical barrier in the ducts between the concentrate and seawater. This means that there will be a small amount of mixing between the two liquids. Because the two liquids are in contact for a short amount of time, the mixing is relatively low. On the RO market the mixing rate is defined as “balanced flow” when HP-out is equal to LP-in. Experience from the market shows that the corresponding increase in membrane operating pressure is about 1 barg.

The customer can reduce mixing by over-flushing the LP feed with excess feed water. See figure below. Over-flushing means energy loss. Optimal over-flushing is

obtained when the energy loss on LP feed is equal to or less than the energy loss caused by the excess pressure at the membrane.

5.7.5 How does the iSave work in an RO system?

The figure below illustrates a typical flow path of an SWRO or BWRO with an iSave.

The high-pressure (HP) concentrate (7) flows to the low-pressure (LP) concentrate outlet

(3).

The LP sea water (2) flows to the HP sea water outlet (5).

The rotor, moving between the high-pressure and low-pressure streams, removes the high-pressure concentrate (7) and replaces it with feed water (2).

The flow rate on the HP sea water outlet (5) is controlled by the iSave alone.

The flow rate on the LP concentrate outlet

(3) is controlled by the sea water feed pump

(1) and the back pressure valve. This means that changing the LP feed flow (2) will not affect HP outlet flow (5) and, vice versa, that changing the HP outlet flow (5) will not affect the LP outlet flow (3).

As LP sea water (2) is flushing the LP concentrate to LP outlet (3), it is essential that the flow on the LP inlet (2) is equal to or slightly higher than the HP inlet (7).

Otherwise there will be an “under-flush” and higher mixing will occur in the HP outlet (5). This higher mixing will result in a slightly higher pressure at the membrane.

The booster pump integrated in the iSave must only overcome the pressure drop from the high-pressure outlet (5) to the high-pressure inlet (7).

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During the RO process operation, water is pumped into the HP-membrane feed (6) by the HP pump (4) and the iSave (5). Almost all water coming from the HP pump (4) penetrates the membranes (8). Only a slight amount of the water is used as lubrication flow in the iSave. The lubrication flow is measured as the difference between the HP pump flow rate (4) and the permeate flow rate (8). The resistance to permeate in the membrane pressurises the HP loop.

The isobaric pressure exchanger technology in an SWRO or BWRO change the HP concentrate into HP seawater that is feed into the HP membranes. The iSave energy recovery technology thus significantly reduces flow needed from the main HP pump (4).

Overall energy consumption of a SWRO or BWRO plant using the iSave depends on the recovery rate.

The operator can change the recovery rate to optimise the RO system performance. Changing the recovery rate in an RO system equipped with iSave is easy. Using the VFD, change the speed of the iSave and thereby the flow in the HP flow rate. Then change the LP feed (2) flow to the iSave to minimise mixing and optimise energy consumption. Make sure that flow and pressure are within the rated parameter of the iSave in question.

5.8 Seawater quality

5.8.1 Pre-filtration

It is important that the incoming water is filtered properly to assure optimum service life of the iSave. A true graded density melt-blown depth filter cartridge rated

at 3 μm is therefore recommended. Poor pre-filtration of the feed water will result in reduced service life of the iSave.

The iSave may request a different pre-filter of the seawater than the HP pump and other components in the RO system.

As the various filters on the market differ greatly, Danfoss High Pressure Pumps recommends using cartridges with consistent, reliable performance and high efficiency, in which fibres are blown continuously onto a central support core.

Danfoss High Pressure Pumps does not recommend cartridges requiring any type of binders or resins.

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.

NB! Filters can be purchased from Danfoss High Pressure Pumps.

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5.8.2 Air bubbles

Large bubbles in a pressurised RO system can result in damage to piping and equipment. All air must be bleed from both the LP and HP before the RO system is pressurised. Special consideration should also be given to air bubbles in feed flow, continuously fed into the HP pump and iSave.

5.8.3 Chemicals

The iSave should not be exposed to chemicals that will damage the RO membranes.

5.9 Initial start up and flushing

Prior to the initial start-up, all piping associated with the iSave unit should be thoroughly flushed to assure that no impurities enter the iSave. Inadequate pre-flushing will strongly affect the life of the iSave and may lead to its eventual breakdown.

It is recommended to disconnect all connections to the iSave and to thoroughly flush the piping before the iSave is connected to the inlet and outlet connections.

It is essential that the water used for the final pre-flush is pre-filtered to a level described in chapter 5.8

It is recommended to install temporary basket strainers at both inlets to the iSave during the initial start-up and commissioning.

Also see “Instruction for start and stop of the SWRO with iSave unit” in appendix 10.1.

5.10 Initial start-up and settings of safety equipment

The high-pressure pump feed water into the high pressure line may be able to generate a pressure higher than the maximum allowable pressure in the system. There is thus a risk of personal injury and/or damage to the iSave.

Depending of the type and size of the feed pump of the RO system, this pump may be able to generate a pressure higher than the maximum allowable pressure in the LP system. There is thus a risk that the iSave or the LP equipment could be damaged by over-pressurisation.

To prevent such over-pressurisation, appropriate relief valves should be used and procedures should be implemented to safeguard the HP and LP sides of the iSave and/or the

RO system.

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5.11 Flushing

RO membranes require periodic flushing to limit biological fouling.

There are two types of flushing: feed water (Seawater) flush and fresh water (Permeate) flush.

Regardless of the flush water used, the water must be pre-filtered to the level described in chapter 5.8. All parts of the iSave must be flushed, i.e. LPand HP flow channels.

Feed water flushing is part of a normal shutdown sequence. After the HP pump has been stopped, the permeate and concentrate production will continue until the high-pressure drops below the osmotic

pressure. Both the iSave and the LP seawater feed pump must run until the conductivity measured at point (7) and (3) are satisfactory. See also P&ID in chapter 5.16.

Fresh water flushing is performed before every extended shutdown of the RO plant. Permeate is simultaneously fed into the iSave at LP in (2), and either to the HP pump inlet (1) or through some other injection point such as the CIP connections or full flow cleaning connection. See also P&ID in chapter 5.16. Permeate may be produced during this flushing process.

NB! Special attention should be given to the pressure in the HP line (7) as the iSave may start to cavitate when it runs at high speed and the pressure in the HP line (7) drops below 3 bargs. This can be avoided by reducing the speed of the iSave to about 750 rpm and keeping the pressure in the HP line at the minimum of 3 barg. At this low pressure the iSave may only run for a maximum of 10 minutes.

Failing to flush the iSave with fresh water before extended shutdowns may result in extensive biological growth and cause corrosion in the iSave and other equipment in the RO system.

5.12 CIP or membrane cleaning

The purpose of membrane cleaning is to reduce scaling and fouling in the membranes. For optimal performance specific chemicals are required, depending on the cause of the pollution. After chemical treatment the system must be flushed with fresh water.

The flush water coming out of the membranes may consist of a large amount of suspended inorganic particles. It is important to assure that these particles are not lead into the iSave.

It is essential that the water used

for the final pre-flush is pre-filtered to a level described in chapter 5.8.

The iSave should not be exposed to chemicals that will damage the

RO membranes

Also see instruction “Membrane cleaning of RO system with iSave unit” in appendix 10.2.

5.13 High pressure remains after shutdown

The HP line of the RO system equipped with an iSave can remain pressurised for a long time after shutdown. Pressure decreases as water slowly leaks through the iSave. If more rapid system depressurisation is required, the system should be bled through a suitable valve on the HP concentrate line.

Always check the pressure in the high-pressure lines before making service in the HP lines or pressurised equipment.

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5.14 Over-pressurisation caused by low pressure isolation

If the low-pressure side of the iSave is blocked and the iSave is exposed to high-pressure, there is a risk that the iSave or the LP piping could be damaged by over-pressurisation.

To prevent such over-pressurisation, appropriate relief valves should be used and procedures should be implemented to assure that the HP of the iSave is depressurised prior to the isolation of the LP side.

5.15 Over-pressurisation caused by the high pressure pump.

The HP pump may be able to generate a pressure higher than the maximum allowable pressure for the iSave or the system – particularly if the HP pump is a positive displacement pump, the pump will be able to generate extremely high levels of pressure.

To prevent such over-pressurisation, appropriate relief valves should be used and procedures should be implemented to assure that the HP of the iSave is protected against excess pressure.

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5.16 Preferred system design and P&ID

VFD

Media filter

Filter

Filter

PI

4

PI

3

<![if ! IE]> <![endif]>M

5

6

3 micron

10 micron

2

PS

PS

17

1

PI

nominel

PI absolut

Permeate

<![if ! IE]> <![endif]>F

<![if ! IE]> <![endif]>F

18

Flowmeter

<![if ! IE]> <![endif]>F

12

Full flow

8

LP in

cleaning

7

*

HP out

11

iSave

10

9

Fresh water

PI

permeate flush

HP in

<![if ! IE]> <![endif]>M

16

28

	13	14			CIP
VFD					27
	PS	PI	20	15
			<![if ! IE]> <![endif]>F
					Drain
19

*Second stage filter: If recommended housing design and cartridges are not used, asecond stage filteris required

Explanation of P&ID setup

•The pressure switch (3) must stop the iSave (11) and the high-pressure pump

(4) at pressures lower than the minimum inlet pressure or higher than the allowable maximum pressure.

•The non-return valve (18) prevents the high pressure flow from the membrane to flow back through the HP pump and into the low pressure piping. This may occur when the high pressure pump stops.

•The pressure relief valve (6) protects the entire 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 build up a very high pressure that will exceed the mechanical strength of the membrane housing, pipes and other accessories.

•The valve (8) bleeds the air out of the system. The valve must be placed at the highest point in the system.

•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.

•Inlet filters assure proper water quality. High quality water extends the service life of the whole system.

•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.

•The pressure switch (13) must stop the iSave when the pressure is lower than the minimum inlet pressure or higher than the maximum pressure.

See “Start and stop” procedure, “Membrane cleaning” procedure instruction in appendices

10.1 and 10.2

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6. On-site installation	6.1 General
	For safety instructions see chapter 3.1
	6.2 Installation and alignment
	The figure below illustrates the major iSave components.
	Fig. 1

Motor

Bolts

Flexible coupling

Bell housing

iSave

Base plate

Port connection

Support bracket (AISI 316)

Bolts

The iSave is connected to the electric motor by the bell housing and a coupling. The bell housing is not suitable for bearing the weight of either the iSave or the motor. Both the iSave and motor must be supported without applying stress/load to the bell housing.

Danfoss provides the iSave with a baseplate and support brackets. Although the baseplate is of a sturdy design, it can flex or bend when it is bolted to the

foundation. The baseplate thus requires a solid foundation such as concrete or rigid steel frame. The baseplate itself must be aligned to avoid bending caused by bolting to an uneven foundation.

A rigid foundation for the iSave assembly is important, and the iSave assembly must be bolted to the foundation.

The bolts used must be of proper design and must be installed in accordance with the bolt manufacturer’s recommendations.

To reduce noise it is recommended to use resilient mounts between the baseplate and the foundation. Make sure that the bolts are properly locked and will stay locked over time.

An unlocked bolt can result in personal injury and/or damage to the iSave.

Misalignment of the base plate may cause stress and/or damage to the bell housing.

6.3 Orientation

The iSave can be mounted horizontally and vertically.

When mounted vertically, the electric motor must be placed above the iSave.

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6.4 Piping and joints

Piping material and schedule is of high importance. The strength of the Victaulic® connections is influenced by the material used for both the Victaulic® clamps and the hard piping.

The hard piping and connections used must be of proper design and must be installed in accordance with the manufacturer’s recommendations.

Hard piping to the iSave must be properly aligned to avoid stress on the iSave port connections. Pipe connections must be aligned as shown in the figures below. Don’t use the iSave as a strain for hard piping.

Correct piping alignment

Misalignment of the hard pipes may place stress on the iSave port connection and may damage the iSave

The hard piping and connections used must be of proper design and must be installed in accordance with the manufacturer’s recommendations.

A failure to comply with this will or may result in personal injury and/or damage to the iSave.

Incorrect piping alignment

Incorrect piping alignment

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6.5 Flexible couplings and flexible hoses

The strength of the Victaulic® connections is influenced by the material used for both the Victaulic® clamps and hose couplings.

The flexible hose and connections used must be of proper design and must be installed in accordance with the manufacturer’s recommendations.

See also “Hose assembly and installation” in appendix 10.5

The flexible hose and connections used must be of proper design and must be installed in accordance with the manufacturer’s recommendations. A failure to comply with this will or may result in personal injury and/or damage to the iSave.

6.6 Mounting of coupling

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

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

A:Flexible coupling

B:Bell housing

C:Motor shaft

6.7 Mounting of bell housing on iSave

The figure below illustrates how to mount the bell housing on the iSave.

Screw the 4 bolts through the bell housing and into the iSave and tighten them to

30 Nm.

6.8 Accessibility

With respect to the service and replacement of the complete iSave unit, it is recommended to maintain sufficient space around the unit.

The space must be sufficient enough to allow for safe lifting of the equipment, with no risk for personal injury and/or damage to the iSave.

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6.9 Drives	6.9.1 Electric motor
	The iSave must only be driven by an electric
	motor.
		Using anything other than an
		electric motor can lead to an
		irreparable fracture of the iSave’s
		internal parts.
	6.9.2 Speed control
	The rotation speed on the electric motor
	can be controlled by a VFD.
	The direction of rotation is engraved with an
	arrow on the iSave.

Checking the direction of rotation can be made by:

1.Looking at the fan in the end of the electric motor.

2.Removing the plug in the bell housing and watch the rotation of coupling.

3.Before assembly the iSave on the electrical motor, check the rotation of the shaft on the electrical motor.

It is required to use a VFD or a soft starter.

A minimum of 10 seconds is required when ramping up the speed from zero to maximum. Otherwise, the torque on the iSave will exceed the maximum limit and may lead to an irreparable fracture of the iSave’s internal parts.

6.9.4 Torque overloads protection on the iSave

The electric motor and iSave must always be protected against overload.

Both at start-up and at continues operation the maximum torque on the iSave must be monitored.

The electric motor must be shut of if the maximum torque of the iSave exceeds the defined limit. The response time of the power shutoff to the iSave must be of maximum 1 second.

If more electric motors are powered by the same soft starter or VFD, each electric motor must be equipped with “torque limit equipment” to protect the iSave against overload.

Special attention has to be on NON PROTECTED – FREE ROTATING shaft on the electrical motor. Ignorance will or could result in personal injury.

•Running the iSave in the wrong direction for more than a few minutes can cause un-intended wear on the iSave.

•If the electric motor is running at a lower speed, extra care must be taken to ensure that the electric motor is NOT overheated. External cooling may be necessary.

6.9.3Starting torque on the iSave/ramping the electric motor

Because of the inertia of the iSave internal parts and the fact that the iSave includes a positive displacement pump, the torque will exceed the maximum allowable torque for the iSave when the speed is not ramped up from zero to maximum.

Below are examples of equipment which can measure the load on the electric motor or limit the torque on the iSave.

1.VFD with integrated current monitoring relays.

2.External current monitoring relays.

3.Torque limiter coupling.

See also examples of “iSave overload protection” equipment in appendix 10.5

The electric motor and iSave must always be protected against overload.

Otherwise, the torque will exceed the maximum limit and may lead to an irreparable fracture of the iSave’s internal parts.

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7.Commissioning, start-up and shutdown

7.1 Safety regulations

The operator ensures that all inspection and installation work is performed by authorised, qualified specialist personnel who are thoroughly familiar with the manual.

Before starting up the iSave and the high pressure pump, make sure that the following requirements are met:

•The iSave has been properly connected to the electric power supply and is equipped with all protection devices in accordance with EN60204-1.

•Check that all motor protections are properly set.

•All safety equipment, auxiliary equipment and connections required are proper connected and operational.

•Check all bolts in all connections and in the foundation of the iSave and the pumps.

7.2Support

Danfoss A/S offers commissioning and service at system manufacturer’s location. Rate quotes are offered upon request.

7.3 Commissioning

Before starting up the iSave and the high pressure pump make sure that the following requirements are met:

All pipes are flushed, free from debris and full of water.

•The iSave has been bled and is full of water.

•At pressure lower than 10 bargs, check the system for leakage.

Slowly raise the pressure in the system and set all pressure switches to the correct limit and continually check all connections for leakage.

•Set pressure relief valve on both low and high pressure at the maximum system pressure.

•Check high pressure hoses for proper assembly and inspect for externa leakage for all connections.

•At low pressure, start the iSave and check direction of rotation.

•Start the system according to the “Start and stop procedure” instructions in appendix. 10.1

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8. Service/

Maintenance

8.1 Safety regulations

The operator ensures that all maintenance, inspection and installation work is performed by authorised, qualified specialist personnel who are thoroughly familiar with the manual.

Before intervening in the iSave/system;

•The power must be shut off and the starting device be locked.

•The pressure in the High Pressure lines must be drained to the Low Pressure side.

•The Water in all connected pipes must be drained.

Always use suitable safety and lifting equipment when handling the iSave, and follow the instructions in chapter 4.3

•When saftey equipment has been adjusted make sure that proper re-adjustment has been made before start-up.

•When the system is re-started after service and maintenance follow the instructions in chapter 7 and in “Start and stop procedures” in

appendix. 10.1

8.2Support

Danfoss A/S offers commissioning and service at the system manufacturer’s location. Rate quotes are offered upon request.

8.3 Maintenance schedule

The schedule of preventive maintenance below will help ensure that the iSave provides years of trouble-free performance.

One day after commissioning:

1.Re-check bolts in the foundation and the baseplate of the iSave and tighten the bolts to specified torque if necessary.

2.Visually inspect all pipe connections / couplings for external leakage.

3.Re-check bolts in all pipe connections / couplings and tighten the bolts to specified torque if necessary.

4.Replace filters if necessary

5.Clean the filter housing and reinstall filters. Make sure no debris enters the system.

Three months after commissioning:

1.Re-check bolts in the foundation and the baseplate of the iSave and tighten the bolts to specified torque if necessary.

2.Re-check alignment of iSave baseplate and iSave.

3.Visually inspect all pipe connections

/couplings for external leakage.

4.Re-check bolts in all pipe connections / couplings and tighten the bolts to specified torque if necessary.

5.Replace filters if necessary.

6.Clean the filter elements and install the new filters. Make sure no debris enters the system.

7.Audibly inspect the iSave assembly. If there is irregular sounds or vibrations inspect the internals parts of the iSave and replace if necessary.

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	8,000 hours of operation after commissioning:		Dimensions of the vanes
	1.	Re-check bolts in the foundation
			iSave type			iSave 21 Plus
		and the baseplate of the iSave and
			Original height (H)			27 mm
		tighten the bolts to specified torque
			Change when H is less than			26 mm
		if necessary.
	2.	Re-check alignment of iSave	Original length (L)			79.84 mm
		baseplate and iSave.
			Change when L is less than			79.64 mm
	3.	Visually inspect all pipe connections
		/ couplings for external leakage.
	4.	Re-check bolts in all pipe
		connections / couplings and tighten
		the bolts to specified torque if
		necessary.
	5.	Replace filters if necessary.
	6.	Clean the filter elements and install
		the new filter. Make sure no debris
		enters the system.
	7.	Audibly inspect the iSave assembly.
		If there is irregular sounds or	Annually:
		vibrations inspect the internals parts
			1. See above section: “8,000 hour of
		of the iSave and replace if necessary.
			operation after commissioning”.
	8.	Visually inspect pump coupling and
			2. See “Operatingand maintenance
		replace if necessary.
			instruction, electric motor” in
	9.	Audibly inspect the iSave assembly.
			appendix 10.6
		If there is irregular sounds or

	vibrations inspect the internals	Follow manufacturer’s recommendations for
	parts of the iSave and replace if
		electric motor service and maintenance.
	necessary.
	10.Check power consumption and flow
	out of the iSave. If there is irregular
	performances inspect the internals
	parts of the iSave and replace if
	necessary.
	11.Inspect and replace, if necessary, the
	vanes in the vane pump.

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9. Trouble-shooting	9.1 Safety regulations
	The operator ensures that all
	inspection and installation work is
	performed by authorised, qualified
	personnel who are thoroughly familiar
	with the manual.

Before intervening in the iSave/system;

•The power must be shut off and the starting device be locked.

•The pressure in the high-pressure lines must be drained to low-pressure side.

•The water in all connected pipes must be drained.

The numbers in () correspond to the preferred system design and P&ID

Problem	Possible cause	Action
VFD can’t start the iSave	VFD is not designed for con-	Choose a VFD that is designed
at initial start-up.	stant torque.	for constant torque.
	Ramp-up settings in the VFD is	Set Ramp-up parameters
	not correct. VFD is tilting.	correct.
	Valve (9) is closed	Open valve (9)
	Pressure in the HP line (5) is	Start the iSave only when the
	too high	pressure in the HP line is low.
Torque on iSave too	Pressure difference from HP-	Clean or change membranes.
high during operation	out (5) to HP-in (10) is too high.
		Debris in the booster pump or
		iSave.
		Wear in the booster pump or
		iSave.
		Design of the basic plant
		doesn’t fit the performance of
		the iSave.
Permeate production is	Valves (6), (7), (8) or (16) are	Repair or change valve.
too low (17).	leaking.
	Internal leakage in iSave	Repair iSave
	HP pump flow (2) is to small	Incorrect speed on the HP
		pump.
		Check the HP pump and repair
		if necessary.
Pressure on the mem-	Fouling on the membranes	Clean the membranes
branes (5) is too high.
	Mixing in the iSave is too high.	Check flow on LP-in (12) and
		adjust flow.
	Flow out of the iSave is too	Check speed on iSave and
	low, causes a recovery rate	change if necessary.
	that is too high.
		Booster pump in the iSave is
		worn out.
		Perform service on the VP.
Pressure on the mem-	Valves (6), (7), (8) or (16) are	Repair or change valve (s).
branes (5) is too low.	leaking.
	Internal leakage in iSave	Repair iSave
	HP pump flow (2) is too small	Incorrect speed on the HP
		pump.
		Check the HP pump and repair
		if necessary.

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Appendices

Energy Recovery Device

iSave 21 Plus

Installation, Operation and

Maintenance Manual

hpp.danfoss.com