Instruction Manual
PN 51-381/rev.D
October 2007
Model 381
pH/ORP Sensor
ESSENTIAL INSTRUCTIONS
READ THIS PAGE BEFORE
PROCEEDING!
Rosemount Analytical designs, manufactures, and tests its products to meet many national and international standards. Because these instruments are sophisticated technical products, you must properly install, use, and maintain them to ensure they continue to operate within their normal specifications. The following instructions must be adhered to and integrated into your safety program when installing, using, and maintaining Rosemount Analytical products. Failure to follow the proper instructions may cause any one of the following situations to occur: Loss of life; personal injury; property damage; damage to this instrument; and warranty invalidation.
•Read all instructions prior to installing, operating, and servicing the product. If this Instruction Manual is not the correct manual, telephone 1-800-654-7768 and the requested manual will be provided. Save this Instruction Manual for future reference.
•If you do not understand any of the instructions, contact your Rosemount representative for clarification.
•Follow all warnings, cautions, and instructions marked on and supplied with the product.
•Inform and educate your personnel in the proper installation, operation, and maintenance of the product.
•Install your equipment as specified in the Installation Instructions of the appropriate Instruction Manual and per applicable local and national codes. Connect all products to the proper electrical and pressure sources.
•To ensure proper performance, use qualified personnel to install, operate, update, program, and maintain the product.
•When replacement parts are required, ensure that qualified people use replacement parts specified by Rosemount. Unauthorized parts and procedures can affect the product’s performance and place the safe operation of your process at risk. Look alike substitutions may result in fire, electrical hazards, or improper operation.
•Ensure that all equipment doors are closed and protective covers are in place, except when maintenance is being performed by qualified persons, to prevent electrical shock and personal injury.
Emerson Process Management
Rosemount Analytical Inc.
2400 Barranca Parkway
Irvine, CA 92606 USA
Tel: (949) 757-8500
Fax: (949) 474-7250
http://www.RAuniloc.com
DANGER
HAZARDOUS AREA INSTALLATION
Installations near flammable liquids or in hazardous area locations must be carefully evaluated by qualified on site safety personnel. This sensor is not Intrinsically Safe or Explosion Proof.
To secure and maintain an intrinsically safe installation, the certified safety barrier, transmitter, and sensor combination must be used. The installation system must comply with the governing approval agency (FM, CSA or BASEEFA/CENELEC) hazardous area classification requirements. Consult your analyzer/transmitter instruction manual for details.
Proper installation, operation and servicing of this sensor in a Hazardous Area Installation is entirely the responsibility of the user.
CAUTION
SENSOR/PROCESS
APPLICATION COMPATIBILITY
The wetted sensor materials may not be compatible with process composition and operating conditions. Application compatibility is entirely the responsibility of the user.
© Rosemount Analytical Inc. 2001
MODEL 381 pH/ORP |
TABLE OF CONTENTS |
MODEL 381 pH/ORP SENSOR
TABLE OF CONTENTS
Section |
Title |
Page |
1.0 |
DESCRIPTION AND SPECIFICATIONS........................................................... |
1 |
1.1 |
Features and Applications................................................................................. |
1 |
1.2 |
Sensor Specifications........................................................................................ |
2 |
1.3 |
Ordering Information ......................................................................................... |
3 |
2.0 |
INSTALLATION ................................................................................................. |
5 |
2.1 |
Installation ......................................................................................................... |
5 |
2.2 |
Submersion Installation (Code 02).................................................................... |
5 |
2.3 |
Insertion Installation (Code 00) ......................................................................... |
7 |
2.4 |
Flow Through Installation (Code 03) ................................................................. |
7 |
2.5 |
Flow Powered Cleaner Installation (Code 04)................................................... |
7 |
2.6 |
Wiring ................................................................................................................ |
7 |
2.7 |
Start-Up and Calibration.................................................................................... |
14 |
2.8 |
Model 381 pH and pHE..................................................................................... |
14 |
2.9 |
Model 381 ORP................................................................................................. |
14 |
3.0 |
MAINTENANCE ................................................................................................ |
15 |
3.1 |
General ............................................................................................................. |
15 |
3.2 |
Periodic Maintenance........................................................................................ |
15 |
3.3 |
Troubleshooting................................................................................................. |
16 |
3.4 |
Preamplifier Troubleshooting ............................................................................ |
18 |
3.5 |
T.C. Element Maintenance ................................................................................ |
18 |
4.0 |
ULTRASONIC CLEANER ................................................................................. |
21 |
4.1 |
Ultrasonic Cleaner............................................................................................. |
21 |
4.2 |
Specifications .................................................................................................... |
21 |
4.3 |
Installation ......................................................................................................... |
21 |
4.4 |
Operation .......................................................................................................... |
22 |
4.5 |
Maintenance...................................................................................................... |
22 |
4.6 |
Replacement Parts............................................................................................ |
22 |
5.0 |
RETURN OF MATERIAL................................................................................... |
25 |
LIST OF TABLES
Table No. |
Title |
Page |
2-1 |
ORP of Saturated Quinhydrone Solutions (in Millivolts).................................... |
14 |
3-1 |
Troubleshooting................................................................................................. |
17 |
3-2 |
Temperature vs. Resistance of Auto TC Element.............................................. |
18 |
3-3 |
Ro & R1 Values for Temperature Compensation Elements .............................. |
18 |
3-4 |
Model 381 Spare Parts...................................................................................... |
19 |
3-5 |
Accessories....................................................................................................... |
19 |
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MODEL 381 pH/ORP |
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TABLE OF CONTENTS |
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MODEL 381 pH/ORP SENSOR |
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LIST OF FIGURES |
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Figure No. |
Title |
Page |
1-1 |
Dimensional Drawing ........................................................................................ |
3 |
1-2 |
Mounting Drawing ............................................................................................. |
3 |
2-1 |
Model 381 Sensor Component Locator Diagram.............................................. |
6 |
2-2 |
Submersion Installation Diagram ...................................................................... |
8 |
2-3 |
Insertion Installation Diagram............................................................................ |
8 |
2-4 |
Flow Through Installation Diagram (Code 03 or 04) ......................................... |
9 |
2-5 |
Installation Details Low Flow Conditions Model 381 (Code 03-04)................... |
9 |
2-6 |
Retro-Fit Kit and Code-04 Flow Powered Cleaner, Model 381 ......................... |
10 |
2-7 |
Flow Through Diagram and Wiring (Code 03 or 04) ......................................... |
11 |
2-8 |
Remote Junction Box with Internal Preamp ...................................................... |
12 |
2-9 |
Wiring with Weatherproof or Div. 2 (Code 2) Junction Box .............................. |
13 |
4-1 |
Model 381 Ultrasonic Cleaner and Wiring......................................................... |
23 |
4-2 |
Dimensional and Component Locator Ultrasonic Generator............................. |
24 |
About This Document
This manual contains instructions for installation and operation of the Model 381 pH/ORP Sensor.
The following list provides notes concerning all revisions of this document.
Rev. Level |
Date |
Notes |
A |
6/94-1/00 |
This is the initial release of the product manual. The manual |
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has been reformatted to reflect the Emerson documentation |
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style and updated to reflect any changes in the product offering. |
B |
5/02 |
Updated multiple drawings throughout manual. |
C |
3/05 |
Updates |
D |
10/07 |
Updated page 3 code 00 insertion is no longer available. |
ii
MODEL 381 pH/ORP |
SECTION 1.0 |
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DESCRIPTION AND SPECIFICATIONS |
SECTION 1.0
DESCRIPTION AND SPECIFICATIONS
•MOLDED POLYETHERSULFONE (PES) BODY provides compatibility with a variety of processes.
•MODULAR DESIGN facilitates maintenance by eliminating terminal and mounting brackets and extraneous hardware.
•INTEGRAL PREAMPLIFIER provides reliable signal transmission.
•DOUBLE JUNCTION, GEL-FILLED, REFERENCE CELL provides high temperature performance, extended service life, and resists the effects of pumping, dilution and contamination.
•OPTIONAL FLOW-POWERED OR ULTRASONIC CLEANING provides trouble-free service in difficult applications.
1.1 FEATURES AND APPLICATIONS
The Model 381 Sensor measures the pH or the Oxidation Reduction Potential (ORP) of aqueous solutions in pipelines, open tanks or ponds. The sensor is used in most industrial applications including SO2 scrubbers, rinse tanks, plating baths, reverse osmosis units, and water and waste treatment plants.
The sensor is housed in a molded PES body and has two O-ring seals with breach lock threads which secure the PES cover. This provides a waterproof union for long operating life and easy removal for routine maintenance.
The modular body design eliminates the need for internal mounting brackets, terminal brackets and screws. All components are screw-type or plug-in- place, allowing for fast simple service.
The integral preamplifier amplifies the high impedance glass electrode signal at the sensor, providing a transmission capability of up to three miles. The Rosemount Analytical Inc. method of preamplification has become the industry standard for reliable pH measurement. In submersion applications at temperatures greater than 80°C, the preamplifier must be located in a remote junction box.
A standard feature of the Model 381 is the double junction, gel-filled reference cell which reduces the need for special applications engineering where unknown reference cell contamination, such as sulfides, may exist. The gel solution maintains its viscosi-
ty at high temperatures, and resists the effect of pumping and dilution, resulting in an extended service life. A choice of wood (Code 20) or ceramic (Code 21) liquid junction is available to provide resistance to fouling and subsequent loss of electrical contact between the reference electrode and process fluid.
In flow applications where crystalline or viscous coatings, such as calcium carbonate or petroleum oils, may coat the electrode surfaces and impede the sensor's performance, the flow-powered cleaning option (Code 04) may be used. A specially designed flow chamber directs the process fluid in a circular path carrying three Teflon1 balls which clean the electrode surface, physically preventing accumulation of coating materials. Flow-powered cleaning is suitable for all hazardous area applications.
In submersion (Code 02) applications, the ultrasonic cleaning option may be specified. This assembly includes the ultrasonic transducer and generator, mounting hardware, and 20 ft. of interconnection cable. Ultrasonic cleaning is not suitable for hazardous area applications.
The Model 381 is compatible with all Rosemount Analytical pH/ORP analyzers. For use with the 1054/2054 Series, 2081 and other pH analyzers which utilize a PT-100 automatic temperature compensator order the Model 381 pHE.
1 Teflon is a registered trademark of E.I. du Pont de Nemours & Co.
1
MODEL 381 pH/ORP |
SECTION 1.0 |
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DESCRIPTION AND SPECIFICATIONS |
1.2 SENSOR SPECIFICATIONS
Materials of Construction:
Body, Cover and Flow Cell: Polyethersulfone (PES).
O-Rings: Viton2.
Measuring Electrode: Glass (and platinum for
Model 381 ORP).
Liquid Junction: Kynar3/wood (Code 20) or
Kynar/ceramic (Code 21).
Process Connections: Submersion: 3/4 inch MNPT.
Insertion: 2 inch MNPT.
Flow Through:3/4 inch MNPT.
Dimensions: (see Figure 1-1).
Measuring Range: pH 0-14
ORP –1500mV to +1500mV
Temperature Compensation: (Model 381 pH only, not required for Model 381 ORP).
Automatic, 0 to 100°C (32 to 212°F).
Pressure Rating: 790 kPa abs at 100°C (100 psig at 212°F)
Cable: Four-conductor, 22 GA, each (0.64 mm dia.), with common shield.
Weight/Shipping Weight: 1.0 kg/1.7 kg (2.2 lb./ 3.7 lb.).
2 Viton is a registered trademark of E.I. du Pont de Nemours & Co. 3 Kynar is a trademark of Elf Atochem North America, Inc.
FIGURE 1-1. Dimensional Drawing
HANDRAIL MOUNTING ACCESSORY
PN 1000856 |
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PN 11275-00 |
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FIGURE 1-2. Mounting
2
MODEL 381 pH/ORP |
SECTION 1.0 |
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DESCRIPTION AND SPECIFICATIONS |
1.3 ORDERING INFORMATION Model pH/ORP Sensor is housed in a PES body suitable for insertion, submersion or flow through installation. The sensor includes an integral preamplifier, measuring electrode, double junction gel-filled reference cell, automatic temperature compensation for pH, and a choice of two cable lengths of either 15 ft. or 50 ft. (4.5 or 15.2 m).
MODEL 381 INSERTION, SUBMERSION, FLOW THROUGH SENSOR
CODE |
FUNCTION |
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pH |
Requires Code 30 |
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ORP |
Requires Code 32 |
(not for use with 1054/1054A ORP Series) |
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pHE |
Requires Code 31 |
(for use with 1054/1054A/2054 Series and 2081) |
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CODE |
INSTALLATION |
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02 |
Submersion |
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03 |
Flow Through |
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04 |
Flow Through with Flow Powered Cleaner (not available with ORP) |
CODE MEASURING ELECTRODE
10General purpose pH
11High pH Electrode, requires Code 21. For sodium concentrations greater than 1% or continuous measurement above 11 pH.
12Ruggedized pH Electrode. For abrasive solutions.
13Platinum ORP Electrode.
14Gold ORP Electrode.
15HF pH Electrode. For HF concentrations less than 100 ppm.
CODE LIQUID JUNCTION
20Wood/KYNAR Liquid Junction
21Ceramic/KYNAR Liquid Junction
CODE TEMPERATURE COMPENSATION
30Automatic T.C., 3.0K ohm. For Models 1003, 1050 & 1181 pH
31Automatic T.C., PT-100. For Models 1054/2054 Series, and 2081
32Automatic T.C., NOT REQUIRED (For Models 1023, 1060 and 1181 ORP)
CODE CABLE
40 15 ft. cable for integral sensor preamp
41 15 ft. coax cable w/BNC connector for remote sensor preamp and integral analyzer preamp (1054A-54/2054-54 only)
42 15 ft. coax cable w/o BNC connector for integral analyzer preamp (1054, 1181-43/44 & 2081-05 only)
43 50 ft. cable for integral sensor preamp
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CODE |
INTEGRAL PREAMPLIFIER |
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50 |
Preamp for Models 1181 pH/ORP & 1050/1060 |
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51 |
Preamp for Models 1003/1023 |
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52 |
Preamp NOT REQUIRED |
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54 |
Preamp for Models 1054/2054 Series, and 2081 |
381 |
pH |
00 |
10 |
20 |
30 |
40 |
51 |
EXAMPLE |
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3 |
4
MODEL 381pH/ORP |
SECTION 2.0 |
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INSTALLATION |
SECTION 2.0
INSTALLATION
2.1 INSTALLATION. Prepare the sensor for installation as follows (see Figure 2-1):
1.Remove the cover from the body by grasping the body and rotating the cover 1/4 turn counterclockwise.
2.When the cover breaks loose from the body, pull the cover straight out.
3.Lubricate the seals of the glass electrode with O- ring lubricant, Rosemount Analytical P/N 2001928, and install the glass electrode in the body. Tighten the electrode nut by hand. DO NOT use tools.
CAUTION
Do not get lubricant on amber tip of glass electrode. It will disrupt the electrical circuit path.
4.Make sure the double junction electrode is threaded tightly.
5.Plug the preamplifier (or remote connector) onto the T.C. and reference electrode pins.
6.Connect the BNC connector from the glass electrode to the preamplifier.
7.Install the body O-rings. Make sure they are clean, and not twisted. Make sure the covers mating surfaces faces are clean.
NOTE
Both body O-rings must be installed and lubricated to ensure a water tight seal. Failure to seal the body properly will result in water damage, in insertion applications.
8.Lubricate the body O-rings with O-ring lubricant, P/N 2001928.
9.Plug the cable connector to the preamplifier, making sure the cable is toward the center of the body.
10.Install the cover on the body so that the threads will engage.
11.Rotate the cover until the triangle on the body aligns with (or falls within) the adjacent mark on the cover.
IMPORTANT!
12.While holding the sensor in an up side down position (see Figure 2-1), remove the 1/4 inch plug from the electrode tip end of the sensor.
13.Install the liquid junction in place of the 1/4 inch plug, using Teflon tape on the liquid junction threads.
CAUTION
DO NOT use pipe joint compound or pipe dope on the threads of the liquid junction. The electrical circuit will be disrupted if the liquid junction is contaminated.
2.2 SUBMERSION INSTALLATION (Code 02). To install the sensor in process proceed as follows (see Figure 2-2):
1.Wrap Teflon tape on 3/4 inch MNPT threads of cover and on standpipe threads. Seal must be water tight. Cable gland is not waterproof. Do not allow water to accumulate in the stand pipe.
CAUTION
Do not use a pipe wrench on the plastic parts. Severe damage could result.
2.Attach a 3/14 inch coupling to the sensor.
3.Attach electrode shroud to 2 inch MNPT.
4.Feed cable through the rigid standpipe.
5.Attach the rigid standpipe to 1 inch coupling.
CAUTION
Rigid stand pipe must be water-tight; cable seal is not waterproof.
6.Tighten all fittings and secure the standpipe to minimize sensor movement. Use flexible conduit at the top of the rigid standpipe to permit removal of the sensor for periodic maintenance.
7.Refer to Section 2.6 and wire the sensor to the transmitter as described.
5
MODEL 381pH/ORP |
SECTION 2.0 |
|
INSTALLATION |
FIGURE 2-1. Model 381 Sensor Component Locator Diagram
6