ECD SMS22 User Manual

ELECTRO-CHEMICAL DEVICES, INC.

SMS-22 Instruction Manual

Sulfide Monitoring System

ELECTRO-CHEMICAL DEVICES, INC.

1681 Kettering, Irvine, CA 92614, USA

Tel: [phone], FAX: [phone]

www.ecdi.com

The information and technical data disclosed in this document may be used and disseminated only for the purposes and to the extent specifically
authorized in writing by Electro-Chemical Devices. Electro-Chemical Devices reserves the right to change published specifications and designs
without prior notice. Part No. 33SMS-22 Revision A

PREFACE

Rev: A - 08/13

Purchasing products from Electro-Chemical Devices, Inc. provides you with the finest liquid analytical instrumentation
available. If this is your first purchase from ECD, please read this manual before installing and commissioning your new
equipment.

If there are any questions concerning this equipment, please contact your local ECD representative, or the factory
directly at:

Electro-Chemical Devices, Inc.

1681 Kettering

Irvine, CA 92614 USA

Telephone: [phone]

FAX: [phone]

Website: www.ecdi.com

Email: [e-mail]

© 2013 Electro-Chemical Devices, Inc. All rights reserved. No part of this manual may be used or reproduced in any form or by any means, or stored in a database or
retrieval system without prior written permission from Electro-Chemical Devices, Inc. Making copies of any part of this manual for any purpose other than personal
use is a violation of United States copyright laws. Document printed in the United States of America.

TABLE OF CONTENTS

SMS-22 Page ii

PREFACE ................................................................................................................................................................................... i

TABLE OF CONTENTS ............................................................................................................................................................... ii

TERMS AND CONDITIONS OF SALE ........................................................................................................................................ vi

RETURN GOODS POLICY ....................................................................................................................................................... viii

IMPORTANT SERVICE INFORMATION .................................................................................................................................. viii

UNPACKING THE INSTRUMENT .............................................................................................................................................. ix

List of Hazards .................................................................................................................................................................... ix

1.0 GENERAL DESCRIPTION ..................................................................................................................................................... 1

1.1 Features ........................................................................................................................................................................ 2

1.2 Specifications ................................................................................................................................................................ 2

2.0 INSTALLATION ................................................................................................................................................................... 4

2.1 MOUNTING ................................................................................................................................................................... 4

2.2 WIRING .......................................................................................................................................................................... 5

2.2.1 Wiring, Sensor(s) .................................................................................................................................................... 5

2.2.2 Wiring, power ........................................................................................................................................................ 5

2.2.3 Wiring, 4-20 mA Outputs ....................................................................................................................................... 5

2.2.4 Wiring, Contact Relay Outputs ............................................................................................................................... 5

2.3 PLUMBING ..................................................................................................................................................................... 6

2.3.1 Sample Requirements ............................................................................................................................................ 6

2.3.2 Connecting the Inlet and Drain fittings .................................................................................................................. 6

2.3.3 Connecting the Reagents ....................................................................................................................................... 6

2.4 INSTALLING the SENSORS ............................................................................................................................................. 7

3.0 OPERATION ....................................................................................................................................................................... 8

3.0.1 RUN Function ......................................................................................................................................................... 8

3.0.2 PRIME Function ...................................................................................................................................................... 8

3.0.3 CALIBRATE Function ............................................................................................................................................... 8

3.1 KEYS ............................................................................................................................................................................... 9

3.2 MENUS .......................................................................................................................................................................... 9

3.2.1 Sulfide Menus ........................................................................................................................................................ 9

3.2.2 pH Menus ............................................................................................................................................................... 9

3.2.3 Configuration and Trim Menu .............................................................................................................................. 10

3.3 MENU FUNCTIONS & OPTIONS ................................................................................................................................... 10

SMS-22 Page iii

3.3.1 Home Screen ........................................................................................................................................................ 10

3.3.2 Graphical Display Screen ...................................................................................................................................... 11

3.3.3 Buffer Menu ......................................................................................................................................................... 11

3.3.4 Set-Up Menu ........................................................................................................................................................ 12

3.3.5 Cycle Settings ....................................................................................................................................................... 13

3.4 OUTPUTS (4-20 mA Channels) .................................................................................................................................... 14

3.4.1 Manual Mode (4-20 mA Hold Function) .............................................................................................................. 14

3.5 ALARM RELAYS ............................................................................................................................................................ 14

4.0 START UP ......................................................................................................................................................................... 15

4.1 POWER UP the ANALYZER ........................................................................................................................................... 15

4.2 CALIBRATION ............................................................................................................................................................... 15

4.2.1 TEMPERATURE SENSORS ..................................................................................................................................... 15

4.2.2 pH SENSOR ........................................................................................................................................................... 16

4.2.3 SULFIDE SENSOR .................................................................................................................................................. 17

5.0 MAINTENANCE ................................................................................................................................................................ 19

5.1 pH and Sulfide electrodes ........................................................................................................................................... 19

5.1.1 Electrode Cartridge Installation ........................................................................................................................... 19

5.1.2 Electrode Cartridge Replacement ........................................................................................................................ 19

5.1.3 Electrode Cleaning ............................................................................................................................................... 19

5.2 Peristaltic Pumps ......................................................................................................................................................... 21

5.2.1 Preparation for Pump/Tubing Service ................................................................................................................. 21

5.2.2 Reagent Pumps .................................................................................................................................................... 22

5.2.3 Sample Pump ....................................................................................................................................................... 22

5.2.4 Tubing and Drain .................................................................................................................................................. 22

6.0 ORDERING INFORMATION .............................................................................................................................................. 24

6.1 ACCESSORIES and SPARE PARTS ................................................................................................................................. 24

7.0 TROUBLESHOOTING ........................................................................................................................................................ 25

8.0 ENGINEERING DOCUMENTATION ................................................................................................................................... 26

8.1 OUTLINE & DIMENSIONAL DRAWING ......................................................................................................................... 26

8.2 WIRING DIAGRAMS ..................................................................................................................................................... 27

Appendix A ............................................................................................................................................................................ 28

C22 Configuration Screens ................................................................................................................................................ 28

Appendix B ............................................................................................................................................................................ 29

SMS-22 Page iv

Reagent Recipes ................................................................................................................................................................ 29

Reagent #1 (16% Potassium Hydroxide) ....................................................................................................................... 29

Reagent #2 (7.5% Hydrochloric Acid) ............................................................................................................................ 30

Appendix C ............................................................................................................................................................................ 30

Scaling Lascar 4-20 mA loop powered indicator ............................................................................................................... 30

SMS-22 Page v

TERMS AND CONDITIONS OF SALE

1. ACCEPTANCE. If this writing differs in any way from the terms and conditions of Buyer's order or if this writing is construed as an acceptance or
as a confirmation acting as an acceptance, then Seller’s acceptance is EXPRESSLY MADE CONDITIONAL ON BUYER’S ASSENT TO ANY TERMS AND
CONDITIONS CONTAINED HEREIN THAT ARE DIFFERENT FROM OR ADDITIONAL TO THOSE CONTAINED IN BUYER'S WRITING. Further, this writing
shall be deemed notice of objection to such terms and conditions of Buyer. If this writing is construed as the offer, acceptance hereof is EXPRESSLY
LIMITED TO THE TERMS AND CONDITIONS CONTAINED HEREIN. In any event, Buyer's acceptance of the goods shall manifest Buyer's assent to

Seller's terms and conditions. No addition to or modification of these terms will be effective, unless set forth in writing and agreed to by Seller.

2. WARRANTIES AND REMEDIES

a. Warranty. Seller warrants to Buyer that it holds and will pass marketable title to the goods sold hereunder. Seller warrants to Buyer that the

items and components manufactured by Seller will be free from defects in material and workmanship (subject, however, to tolerances and
variances permitted by the trade hereunder) for a period one (1) year for non-consumable products. Consumable electrodes and sensors have a
conditional warranty based shelf life and process conditions and is determined by Seller.

b. Exclusion and Conditions. Seller’s obligations with respect to the express warranties and remedies contained herein are conditioned on the
following: (i) Buyer's return of the non-conforming goods, if authorized by Seller: (ii) Buyer shall not assign its rights under these express warranties
and any attempted assignment shall render such warranties, but not any disclaimers or limitations, void and the goods sold shall be sold AS IS; and
(iii) all products shall be carefully inspected for damage by Buyer upon receipt, be properly calibrated for Buyer's particular use, and be used,
repaired, and maintained by Buyer in accordance with the instructions set forth in Seller’s product literature. Repair and maintenance by non­qualified personnel, product subjected to misuse or negligence, and/or damaged during shipment will invalidate the warranty, as will the use of
non-approved consumables or spare parts. As with any other sophisticated product, it is essential, and a condition of Seller’s warranty, that all
personnel using the product be fully acquainted with its use, capabilities and limitations as set forth in the applicable product literature.

3. DISCLAIMER OF IMPLIED WARRANTIES. Seller gives no warranties except those expressly contained herein. Seller disclaims all other warranties
implied by law usage of the trade, course of dealing or course of performance including, but not limited to, the Implied warranties of

MERCHANTABILITY and fitness for a particular purpose.

4. LIMITATIONS OF LIABILITY. The following limitations of Seller's liability are acknowledged by the parties to be fair and reasonable and shall apply

to any act or omission hereunder, and to any breach of this contract of which these terms and conditions form a part:

a. Disclaimer of Damage. In no event shall Seller be liable for special, indirect, consequential or incidental damages whether arising under
contract, warranty, tort, strict liability or any other theory of liability. Such damages include but are not limited to loss of profits, loss of use of

goods, damage to property, and claims of third parties.

b. Suitability. Buyer acknowledges that it alone has determined the intended purpose and suitability of the goods sold hereunder. It is expressly
agreed by the parties that any technical or other advice given by the Seller with respect to the use of the goods or services is given without charge
and at Buyer's risk; therefore Seller assumes no obligation or liability for the advice given or results obtained.

c. Notice and Time of Claims.

i. Buyer agrees to check and inspect all products against shipping papers and for damage or shortage upon receipt of goods at destination.

ii. Every claim for shortage, damage in transit, or other cause visible upon inspection shall be deemed waived by the Buyer, or the Buyer’s customer

in the case of resale, unless delivered in writing to Seller by Buyer thirty (30) days from the tender of delivery of the goods to Buyer, provided,
however, that claims for shortage must be made within seven (7) days of receipt.

iii. The parties expressly waive the statute of limitations and agree that any legal proceeding for any breach of this contract shall be waived unless
filed within one (1) year after the accrual of the cause of action thereof.

5. FORCE MAJEURE. Seller shall not be liable for any delay in delivery, or failure to deliver, due to any cause beyond the Seller’s control including
but not limited to fires, floods, or other forces of the elements; strikes, or other labor disputes; accidents to machinery; acts of sabotage; riots;
precedence or priorities granted at the request or for the benefit, directly or indirectly of the federal or any state government or any subdivision or
agency thereof; delay in transportation or lack of transportation facilities; restrictions imposed by federal, state or other governmental legislation
or rules or regulations thereof. If Seller, in its sole discretion, determines that Seller’s performance hereunder would result in a loss to Seller’s on

SMS-22 Page vi

this sale as computed under Seller’s normal accounting procedures because of causes beyond Seller's control, then the Seller may terminate this
agreement in whole or in part without liability for any delay in the delivery of, or failure to deliver, the goods sold hereunder

6. TAXES AND OTHER CHARGES. The Buyer will pay, or reimburse Seller if it pays, any and all taxes or tariffs or any other similar charges imposed
upon this contract, the goods covered hereby or the delivery or use or resale thereof.

7. FREIGHT CHARGES. If the sale hereunder is other than F.O.B. Seller's facility, this acknowledgement is based upon the freight charges now in
effect. In the event of an increase or decrease in applicable freight charges before the goods are shipped, such charge in freight will be for the
Buyer's account.

8. PRICES AND DELIVERY. Prices quoted herein are F.O.B. shipping point. Deliveries specified are only our best estimate and are subject to change.
This quotation is based upon freight charges now in effect. Buyer will be invoiced at the freight charge prevailing at the date of shipment. Prices are
firm for orders meeting Seller's normal shipping schedules. If shipments are held or postponed for any reason other than Seller's fault, and a price
increase becomes effective during the period of such hold or postponement, the increase will apply to all shipments that are held or postponed
thirty (30) days or more from the effective date of the increase.

9. PAYMENTS. If in the judgment of Seller the financial condition of Buyer at any time prior to shipment does not justify the terms of payment
specified, Seller may cancel the order, withhold shipment, and/or require full or partial payment in advance. If payment is not made when due,
Seller may suspend all future delivery or other performance with respect to Buyer without liability or penalty and, in addition to all other sums
payable hereunder, Buyer shall pay to Seller (i) the reasonable costs and expenses incurred by Seller in connection with all actions taken to enforce
collection or to preserve and protect Seller’s rights hereunder, whether by legal proceedings or otherwise, including without limitation reasonable
attorneys’ fees, court costs and other expenses and (ii) interest on all amounts unpaid after 30 days charged at the monthly rate of 1-1/2% or the
highest rate permitted by law, whichever is lower.

10. CANCELLATION OR ALTERATION. Buyer may not alter or cancel any order without Seller’s written consent. For any order altered or cancelled
with Seller's consent, Buyer must pay for all expenses and labor incurred up to the time of Seller’s consent, plus a reasonable percentage for profit.
Any order delayed or deferred by Buyer will be subject to price escalation for increased costs of production, and any other expenses caused by the
delay. Material on such orders will be stored at Buyer's risk. Seller reserves the right to invoice Buyer and require payment before shipment of any
delayed or deferred order.

11. TITLE AND RISK OF LOSS. Title and risk of loss shall pass to buyer at Irvine, California, unless otherwise specified in the contract. If delivery is
made by common carrier, risk of loss shall pass upon delivery to the carrier. Claims for loss or damage in transit must be made by Buyer to the
carrier. Seller accepts no responsibility for loss or damage to product in transit.

12. PATENT OR TRADEMARK INFRINGEMENT. If the goods sold hereunder are to be prepared for manufacture according to Buyers specification,
Buyer shall indemnify Seller against any claim or liability for patent, trademark, service mark or trade name infringement on account of
preparation, manufacture and/or sale.

13. NON-WAIVER. If Government Contract Regulations require the addition, deletion, or modification of these terms and conditions upon prior
notification to Seller and Seller's written acceptance thereof, such changes shall become a part of these terms and conditions. Seller shall not be
bound by any Government Contract Regulations applicable to Buyer’s contracts with the U.S. Government unless Buyer has expressly
acknowledged, on the face of this document, the applicability of such Regulations to the transaction between Buyer and Seller contemplated
herein. Absent such acknowledgement, Seller is making the assumption in issuing this document that no such Regulations apply.

14. JURISDICTION. All such disputes shall be resolved in a court of competent jurisdiction in Orange County, California. Buyer hereby consents to
the jurisdiction of the State and Federal Courts sitting in Orange County. Not withstanding the above, should either party contest the jurisdiction of
such courts, the other party may institute its suit in any court of competent jurisdiction.

15. APPLICABLE LAW. All questions arising hereunder or in connection with the quotations or any order submitted in connection therewith and/or
the performance of the parties hereunder shall be interpreted and resolved in accordance with the laws of the state of California without regard to
its conflict of law provisions and excluding the United Nations Convention on the International Sale of Goods.

SMS-22 Page vii

RETURN GOODS POLICY

All requests for returned goods must be initiated through our Customer Service Department. Please call our phone number (949)
336-6060 with the specifics of your request. The following conditions must be satisfied for consideration of applicable credit for the
return of products purchased from Electro-Chemical Devices:

1) The item is unused and in the original package.

2) The item was shipped directly from Electro-Chemical Devices.

3) The item has not been damaged in shipment to Electro-Chemical Devices.

4) Items containing date-sensitive parts such as electrodes, must be returned within 1 month of the invoiced date.

5) Items without date-sensitive parts must be returned within 3 months of the invoiced date.

A Return Merchandize Authorization Number must be obtained from Customer Service and be provided on all paperwork and
packaging. To obtain a Return Merchandize Authorization Number, please provide the reason for return, the date of purchase, your
original purchase order number, and either our order number or our invoice number. The issuance of a Return Merchandize
Authorization Number is a verbal approval for return only and does not guarantee credit or allowance. Returned goods must be
received within 30 days of the issuance date of the Return Merchandize Authorization Number or it will become null and void.

Necessary physical and mechanical inspection is completed upon receipt of the item. Applicable credit or equivalent allowance is
determined after inspection of the returned item. If all of the above conditions are met, and the item has been approved to return
to our stock, a restocking charge of 25% of the purchase price is deducted from the applicable credit.

IMPORTANT SERVICE INFORMATION

Use only factory authorized components for repair. Tampering or unauthorized substitution of components may adversely affect the
operation of this product and may void the warranty.

If service or repair is required, please obtain the serial number(s) or sales order number of the product(s) in question and contact
ECD’s Service Department at:

[phone] (USA/Canada) or [phone]

or email [e-mail]

A Return Material Authorization (RMA) number must be obtained from the service department before returning any material to
ECD. All material returned to ECD shall be shipped prepaid to the factory.

SMS-22 Page viii

Hazard of electrical shock

Involved parts:

Hazard of chemical burns

Involved parts:

Harmful

Involved parts:

Warning of general hazard

UNPACKING THE INSTRUMENT

Your Electro-Chemical Devices instrument has been carefully packaged to protect it from damage during shipment and
dry storage. Upon receipt please follow the procedure outlined below.

1. Before unpacking, inspect the condition of the shipping container to verify proper handling by the carrier. If

damage is noted, save the shipping container as proof of mishandling for the carrier.

2. Check the contents of the shipping container with the items and quantities shown on the packing list.

Immediately report any discrepancies to ECD.

3. Save the original packing material until you are satisfied with the contents. In the event the product(s) must be

returned to ECD, the packing material will allow you to properly ship it to ECD.

4. Familiarize yourself with the instrument before installation, and follow proper installation and wiring

procedures.

List of Hazards

This symbol is used to present a hazard of severe electric shock or
electrocution. All controls and maintenance on electrical devices
labelled with this symbol should be made by qualified personnel in
accordance with national or local regulations. Qualified Personnel
means person who has been fully trained and has professional
experience to avoid electricity hazards and dangers. To avoid
potential fatal electrical shock and/or ana ly z er damage always
disconnect input power to analyzer before servicing.

·main power supply

·peristaltic pump

motor

·input terminal

This symbol is used to present an hazard of severe burns and seroius injury
for dangerous chemicals manipulation. All handling and manipulations
operations maintenance on chemical s l abell ed with thi symbol s hould be
made by qualified personnel in accordance with national or local regulations.
Qualified Personnel means person who has been fully trained and has
professional experience to avoid chemical hazards and dangers. Before to
proceed to every handling of chemicals and to proceed with service
operations, read the material safety data sheets supplied with each chemical
to take all the necessary precautions when handling.

Specific indication depending on the parameter analysed and the chemical
colorimetric method used. See appendix of the manual.

This symbol means that is necessary read this manual before to proceed to
any service operation to know exactly how to operate in proper way. Only
qualified personnel or bbbbully trained on analyzer use and maintenance is
allowed to proceed with service operations on the unit.

· fluidics section

· reagent container

· fluidics section

· reagent container

SMS-22 Page ix

1.0 GENERAL DESCRIPTION

The ECD SMS-22 Sulfide Measurement System is an all in one
analyzer for the continuous measurement of sulfide ions in aqueous
solution. Sulfide ions are present in well water, municipal waste
water and waste waters from refineries, tanneries, chemical plants
and paper and pulp facilities.

Hydrogen sulfide (H
that “rotten egg” odor. H

S) is a gas that dissolves in water and gives it

2

S exists as a dissolved gas in acidic water,

2

as bisulfide ions (HS-) in water with pH values above pH 7 and as
sulfide ions (S

-2

) in water with very high pH values, values above pH

12.

The ECD SMS-22 uses a sulfide ion selective electrode (ISE) to measure the total amount of sulfide
present in the sample. The measurement must be made at high pH levels where S

-2

exists. Potassium
hydroxide (KOH) is added to raise the pH of the sample to around pH 13 and a pH electrode measures
the actual pH. Sulfide and bisulfide exist in a pH dependent equilibrium with the ratio dependent on the
pH. The sulfide ISE measures the sulfide present in the sample and the pH measurement infers what
percentage of the total sulfide was measured. The C22 calculates and displays the Total sulfide present.

The highly caustic sample is then neutralized with HCl and the pH is measured and displayed to verify
the neutralization. The KOH is neutralized with HCl producing potassium chloride salt (KCl) and water.
The neutralized sample can be disposed of as waste or returned to the water supply. Each cycle uses
about 1 ml of caustic and 1 ml of acid.

The analyzer is set to run 6 minute analysis cycles (10 cycles per hour) but can easily be programmed to
run 12 minute cycles (5 cycles per hour) or 30 minute cycles(2 cycles per hour). Running continuously at
10 cycles per hour, the SMS-22 uses 10 liters (2.5 gallons) of each reagent per month and at 2 cycles per
hour less than 2 liters (0.5 gallon) per month.

The 6 minute cycle is composed of 3 x 2 minute cycles.

1. Sample fill 0:00-0:30 minutes: seconds

2. Drain 1:50-1:59 minutes: seconds

3. Sample fill 2:00-2:30 minutes: seconds

4. Drain 3:50-3:59 minutes: seconds

5. Sample fill 4:00-4:30 minutes: seconds

Add KOH 4:00-4:30 minutes: seconds

6. Measure sulfide 4:50-4:59 minutes: seconds

7. Add HCl 5:00-5:30 minutes: seconds

8. Measure pH 5:40-5:49 minutes: seconds

9. Drain 5:50-5:59 minutes: seconds

SMS-22 Page 1

1.1 Features

• Continuously measures the Total Sulfide present in

aqueous solutions up to 500 ppm

• Plumb and Play Design, Ready to Use, factory Calibrated

• Grey, molded fiberglass IP66 enclosure with Clear

polycarbonate cover, easy installation, NEMA 4X

• S10 Sulfide and S10 pH electrodes

• Reliable and Easily serviced Peristaltic pumps for

reagents and sample

• C22 Analyzer Capability, Dual Measurements, multiple

outputs, timers, relays, logic gates, 110/220 VAC Power

1.2 Specifications

Sensor and Flow Train

Sensors:

Sulfide Ion Electrode, Ag
pH Electrode, General purpose pH glass with double junction reference cell

Measurement Range:

Sulfide: 0.02 to 500 ppm
pH: 0 to 14 pH

Reagent Use:

Less than 2 gallons each per month of 16% KOH and 7.5% HCl at 10 cycles per hour

Operating Temperature:

0° C to 50° C (32° F to 122° F)

Sample Flow rate:

Sample from ambient pressure
Minimum flow, 1.5 L/hour

Wetted Materials:

PVC, PP, PTFE, Glass, 316 SS, silicone, Norprene tubing

Process Connections:

Input ⅜” Tubing, Drain ⅜” Tubing

Cycle Time:

User Defined, 6 minutes (default), 12 minutes or 30 minutes

Analyzer Settings

Run, Calibrate, Prime

C22 Analyzer:

Measurements:

Sulfide: 0.02 to 500 ppm
pH: 0 to 14 pH
Temperature: 0° C to 100° C (32° F to 212° F)

S solid state pellet with double junction reference cell

2

SMS-22 Page 2

pH Compensation:

pH 11 - 14 (accuracy degrades rapidly below 11 pH)

Display:

2.5” X 1.75” backlit LCD, 4 lines for Text & Graphical

Enclosure:

NEMA 4X, LxWxD: 5.7” x 5.7” x 7

Outputs:

(1) 4-20 mA for Sulfide set to Sensors Range, user configurable
(1) 4-20 mA for pH set 0-14 pH, user configurable

Alarm Relay Ratings:

(4) SPDT 230 VAC/5A or 30 VDC / 5A resistive max.

Input Power

110/220 VAC @ 50/60 Hz
24 VDC (12 to 50 VDC) @ 1.5 A

Display

Lascar 4-20 mA loop Powered indicator
Model: DPM 742-BL

SMS-22 Page 3

2.0 INSTALLATION

Mount the SMS-22 in a location where there is easy access to the analyzer and sensors. Install the
system in an area where vibrations, electromagnetic and radio frequency interference are minimized or
absent.
Do not mount in direct sunlight or areas of extreme heat. The SMS-22 is suitable for outdoor use if
mounted with a protective cover or sunshield.
Provide access to drain or atmospheric sample return. Sample Conditioning Cell overflow and spent
sample must drain to atmospheric pressure, no back pressure.
Reagents should be stored below the SMS – 22 or within 3 feet (1 meter) to either side.

2.1 MOUNTING

The SMS-22 can be direct mounted through the four corner holes of the enclosure or by using the four
fiber glass reinforced polyamide brackets which are mounted directly to the rear of the box.

SMS-22 Page 4