Rosemount 498CL pH-Independent Free Chlorine Sensor Quick start guide

Brand: Rosemount

Model: 498CL pH-Independent Free Chlorine Sensor

Type: Quick start guide

Quick Start Guide

LIQ-QSG-498CL, Rev M

July 2017

Rosemount

™

498CL

pH-Independent Free Chlorine Sensor

Contents

Chapter 1 Plan ..................................................................................................................................1

1.1 Unpacking and inspection .............................................................................................................. 1

1.2 Specifications .................................................................................................................................1

Chapter 2 Install ...............................................................................................................................3

Chapter 3 Wire .................................................................................................................................5

Chapter 4 Maintenance .................................................................................................................... 7

4.1 Cleaning the membrane .................................................................................................................7

4.2 Replacing the electrolyte slurry and membrane ............................................................................. 7

4.3 Storage .......................................................................................................................................... 9

4.4 Rejuvenating a sensor following improper storage ......................................................................... 9

Chapter 5 Accessories .................................................................................................................... 11

Contents

Quick Start Guide i

Contents

ii Rosemount 498CL

1 Plan

1.1 Unpacking and inspection

1. Inspect the shipping container. If it is damaged, contact the shipper immediately for

instructions.

2. Save the box.

3. If there is no apparent damage, unpack the container. Be sure all items shown on the

packing list are present. If items are missing, notify Rosemount immediately.

1.2 Specifications

Sensor specificationsTable 1-1:

Physical characteristics Specifications

Linear range 0 to 20 ppm (mg/L) as Cl

. For higher ranges, consult the fac-

tory.

Pressure Sample must drain to open atmosphere. No back pressure

allowed.

Temperature (operating) 0 to 50 °C (32 to 122 °F)

Wetted materials PVC, polyethersulfone, polyester, Viton

(1)

, silicone, and 316

stainless steel.

Cathode Gold mesh

Accuracy Accuracy depends on the accuracy of the chemical test used

to calibrate the sensor.

Linearity between 0 and 20 ppm 1% (per IEC 60746)

Linearity between 0 and 2 ppm ±0.05 ppm following calibration at about 2 ppm

Sensitivity to pH Between 6.5 and 10 sensor signal changes <4% per unit

change in pH. Below pH 6.5, the change is < 1% per unit

change in pH.

Sample conductivity > 10 µS/cm

Interferences Monochloramine, dichloramine, and permanganate

Response time < 2 minutes to 90% of final value following step change at

1.2 gal/hr (75 mL/min) and 25 °C (77 °F)

Electrolyte life 3 months (approx.)

Cable length (standard integral cable) 25 ft (7.6 m)

Cable length (maximum) 300 ft (91 m)

Sample flow 1.2 gal/hr (75 mL/min). Changing flow from 0.5 to 2.5 gph

(30 to 160 mL/min) increases the sensor signal by about

30%. Increasing flow increases pH dependence.

Plan

Quick Start Guide 1

Sensor specifications (continued)Table 1-1:

Physical characteristics Specifications

Process connections Sensor must be used in flow cell PN 24091-01

Weight/shipping weight

(2)

Sensor with integral cable: 2 lb/3 lb (1.0 kg/1.5 kg)

Sensor with VP connector: 1 lb/2 lb (0.5 kg/1.0 kg)

(1) Viton is a registered trademark of EI duPont de Nemours.

(2) Weights and shipping weights are rounded up to the nearest whole pound or 0.5 kg.

Flow cell specificationsTable 1-2:

Part number

(1)

24091-01 (low flow cell with bubble sweeping nozzle)

Wetted materials Polycarbonate, polyester, 316 stainless steel, and silicone

Maximm inlet pressure 65 psig (549 kPa abs)

Process connections 1/4 in. OD tubing compression fitting or 1/4 in. FNPT

(1) Sold separately

CAUTION!

SENSOR/PROCESS APPLICATION COMPATIBILITY

The wetted sensor materials may not be compatible with process composition and operating

conditions. Application compatibility is entirely the responsiblity of the user.

Plan

2 Rosemount 498CL

2 Install

Complete the following steps to install the sensor in the low flow cell.

The sensor leaves the factory with a shipping membrane in place.

CAUTION!

EQUIPMENT DAMAGE

Do not remove the shipping membrane until you are ready to put the sensor in service.

Procedure

1. Remove the red protective cap from the sensor.

2. Holding the membrane end pointing up (cable end pointing down), unscrew the

retainer cap and remove the shipping membrane.

See Figure 2-1. It is not necessary to remove the O-ring. Save the shipping

membrane. It should be reinstalled when the sensor is not in use.

Rosemount 498CL SensorFigure 2-1:

3. Still holding the membrane end pointing up, install the chlorine membrane.

The chlorine membrane is in the plastic bag attached to the sensor.

4. Screw the retainer back in place.

Place the sensor in the flow cell and start the flow.

CAUTION!

EQUIPMENT DAMAGE

Do not store or operate the sensor for more than about 45 minutes in a non-flowing

sample.

The sensor must drain to open atmosphere without back pressure. Do not leave the

sensor in the air.

Install

Quick Start Guide 3

InstallationFigure 2-2:

The plastic adapter shipped with the flow cell is not used.

Keep sample flow constant and between 1 and 2 gph (60 to 120 mL/min).

Install

4 Rosemount 498CL

3 Wire

NOTICE

For additional wiring information on this product, including sensor combinations not shown

here, please refer to the Liquid Transmitter Wiring Diagrams.

Rosemount 498CL Sensor Wiring to Rosemount 1056 and 56

Transmitters

Figure 3-1:

Wire

Quick Start Guide 5

Pin out Diagram for Rosemout 498CL-01-VP Sensor (Top View of

Connector End of Sensor)

Figure 3-2:

Wire

6 Rosemount 498CL

4 Maintenance

The sensor requires routine maintenance which includes cleaning the membrane as well as

periodically replacing the membrane and fill slurry. The fill slurry and membrane should be

replaced at approximately three-month intervals. The frequency of cleaning can be

determined only by experience.

4.1 Cleaning the membrane

Keep the membrane clean and free from dirt and algae. Clean the membrane with water

sprayed from a wash bottle.

CAUTION!

EQUIPMENT DAMAGE

Do not use tissues to clean the membrane. Touching the membrane may bend the cathode and

permanently damage the sensor.

4.2 Replacing the electrolyte slurry and membrane

Complete the following steps to replace the electrolyte slurry and membrane in the

sensor.

WARNING!

HARMFUL SUBSTANCE

Fill solution and solid may cause irritation. Avoid contact with skin and eyes. May be harmful if

swallowed. Read and follow manual.

Procedure

1. Unscrew the membrane retainer and remove the membrane assembly and O-ring.

See Figure 2-1.

2. Remove the fill plug.

3. Empty all remaining fill slurry from the sensor. Rinse with deionized water until there

is no significant amount of solid left in the sensor.

4. Place a few drops of water in the replacement membrane assembly and place it on

the mesh cathode.

Maintenance

Quick Start Guide 7

CAUTION!

EQUIPMENT DAMAGE

Do not touch the mesh cathode. Doing so may bend the mesh and permanently damage

the sensor.

5. Screw the membrane retainer into place.

6. Obtain one bottle of saturated succinic acid (PN 9210381, 40 mL) and one bottle of

succinic acid crystals (PN 9210379, 40 g) from the electrolyte kit. Remove the red

cap from the fill spout on each bottle.

7. Using a razor blade or scissors, cut the fill spout on the bottle of dry succinic acid just

below the line on the spout.

8. Hold the sensor with the membrane end pointed slightly upward. Insert the spout of

the bottle of succinic acid solution into the fill port. Squeeze the bottle until half of

the solution has been transferred to the electrolyte chamber.

9. Pour the solid succinic acid crystals into the fill port.

If the crystals accumulate in the fill hole, shake or tap the sensor to gently unblock

the port.

10. Use the remainder of the succinic acid solution to rinse crystals adhering to the

threads in the sensor. Keep adding solution until it overflows the fill port. Tap the

sensor a few times to be sure no air bubbles are trapped in the sensor.

11. Screw the fill plug back into place until it is flush with the body.

12. Hold the sensor with the membrane end pointing down and give it a few shakes as

though shaking down a fever thermometer.

Shaking helps clear bubbles that might have become trapped behind the mesh

cathode.

The sensor may require several hours operating at the polarizing voltage to equilibrate

after the electrolyte had been replaced.

NOTICE

Be sure to place the sensor in flowing, chlorinated water for equilibration.

Maintenance

8 Rosemount 498CL

4.3 Storage

The sensor must be stored in a flowing sample. Minimum sample flow is 0.5 gph

(30 mL/min). Do not let the membrane dry out. If the sensor cannot be stored in a flowing

sample:

1. Turn off power to the transmitter.

2. Remove the sensor from the flow cell.

3. Replace the membrane with the shipping membrane provided with the sensor.

For a replacement shipping membrane, order PN 23501-00.

4. To protect the sensor from physical damage, store it in the dry flow cell.

4.4 Rejuvenating a sensor following improper

storage

If the sensor is stored in a stagnant sample for more than a day or two, it can become

contaminated with copper. Corrosion of the external copper electrode produces copper

ions, which diffuse through the membrane into the sensor. If the sensor was powered up

during storage, copper will plate out on the cathode. If the sensor was not powered up, the

copper will start plating out as soon as the polarizing voltage is applied. Once copper has

coated the cathode, the sensor zero current will become very high, and the sensor will be

unusable until the cathode has been cleaned.

1. If the sensor was not powered up during storage, do not apply power. Complete the

following steps:

a. Empty the fill slurry and thoroughly rinse the sensor with deionized water.

b. Refill the sensor with fresh fill slurry.

c. Let the sensor run in flowing chlorinated water overnight.

d. Zero and calibrate the sensor.

See the transmitter instruction manual for details. The zero current should be

less than about 100 nA.

2. If the sensor was powered up during storage, the cathode is probably coated with

metallic copper. Complete the following steps:

a. Disconnect the sensor from the transmitter.

b. Remove the membrane and clean out the fill slurry.

c. Immerse the mesh cathode in 10% nitric acid solution (10 mL of concentrated

nitric acid in 90 mL of water) for about 5 minutes.

d. Rinse thoroughly with deionized water.

e. Refill the sensor with fresh slurry and install a new membrane.

f. Let the sensor run overnight in flowing chlorinated water.

g. Zero and calibrate the sensor.

Maintenance

Quick Start Guide 9

The zero current should be less than about 100 nA.

Maintenance

10 Rosemount 498CL

5 Accessories

Rosemount 498CL pH-Independent Free Chlorine Sensor accessoriesTable 5-1:

Part number Description

24150-01 Variopol, 6.0 interconnecting cable, 10 ft (3 m)

24150-02 Variopol 6.0 interconnecting cable, 50 ft (15 m)

24091-01 Cell, low flow, 1/4 in. inlet and outlet, with bubble shedding nozzle

33970-00 Fill plug

33521-03 Membrane retainer cap

23501-10 pH-independent free chlorine membrane assembly, includes one

membrane assembly and one O-ring

23502-10 pH-independent free chlorine membrane assembly, includes three

membrane assemblies and three O-rings

24146-00 pH-independent free chlorine sensor electrolyte kit, includes three

bottles of saturated succinic acid solution and three bottles of suc-

cinic acid crystals

Accessories

Quick Start Guide 11

LIQ-QSG-498CL

Rev M

2017

www.Emerson.com/RosemountLiquidAnalysis

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Electric Co. Rosemount is a mark of one of the Emerson family of

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Rosemount 498CL pH-Independent Free Chlorine Sensor Quick start guide

Rosemount 498CL pH-Independent Free Chlorine Sensor Quick start guide

Rosemount 498CL pH-Independent Free Chlorine Sensor Quick start guide

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