Yokogawa PH8EFP KCI Filling type pH Sensor

Introduction

This manual covers the PH8EFP KCI Filling type pH Sensor. It also lists related items described in other manuals.

Related Manuals

Trademark Acknowledgments

• FLEXA and FLXA are trademarks or registered trademarks of Yokogawa Electric Corporation.
• All other company and product names mentioned in this user's manual are trademarks or registered trademarks of their respective companies.
• TM and ® symbols are not used to indicate trademarks or registered trademarks in this user's manual.

For the Safe Use of this Equipment

Notes on Handling User's Manuals

• Provide user's manuals to end users for convenient reference.
• Read the information thoroughly before using the product.
• The purpose of these manuals is to describe the product's functional details, not to warrant its suitability for any particular purpose.
• User's manuals may not be transferred or reproduced without prior written consent from YOKOGAWA.
• YOKOGAWA reserves the right to make improvements to the manuals and product at any time without notice.
• Contact a Yokogawa sales representative or local distributor for any questions, mistakes, or omissions.

Safety, Protection, and Modification of the Product

• Observe safety precautions in this manual for safe operation of the product and the system it controls. Yokogawa assumes no liability for safety if instructions are not followed.
• Using the instrument in a manner not specified in this manual may impair its protection.
• Prepare any necessary protection or safety circuits separately.
• Use only spare parts approved by Yokogawa Electric Corporation.
• Modification of the product is strictly prohibited.

Safety Symbols:

• WARNING: Indicates risks of injury, electric shock, or fatalities. Follow manual instructions carefully.
• CAUTION: Indicates potential for instrument or software damage, or system failure. Refer to manual instructions.
• CAUTION: Provides essential information for understanding operations and functions.
• NOTE: Provides complementary information.

Warning and Disclaimer

The product is provided on an “as is” basis. Yokogawa shall have no liability for any direct or indirect loss or damage arising from the use of the product or any defect that Yokogawa cannot predict.

Compliance with Simple Apparatus Requirements

The PH8EFP meets the simple apparatus requirements defined in the following standards. Note: TIIS certified types cannot be connected.

Applicable Standards:

• ANSI/ISA-60079-11 (2014)
• ANSI/ISA-60079-0 (2009)
• CAN/CSA-C22.2 NO. 60079-11:14
• CAN/CSA-C22.2 NO. 60079-0:11
• GB 3836.4-2010
• Korean: 방호장치 의무안전인증 고시

Conditions of Use:

1. Use in combination with an internally isolated transmitter, or with a transmitter in combination with an isolated barrier. The FLXA21 is internally isolated.
2. Upper limit of the process temperature is indicated below when the sensor is used in combination with a Yokogawa transmitter.

For FLXA21:

Model and suffix code: FLXA21-D-□-D-EA-P1-□-A-N-LA-N-NN

• The first blank can be any value.
• The second blank must be NN or P1.
• Any option code is available.

For PH202S:

Model and suffix code: PH202S-□-E

• The blank must be C or U.
• No PH202S models meet Korean explosion proof standards.
• Any option code is available.

Upper Limit of Process Temperature on the PH8EFP

*1: Take care about the upper limit of 100°C for temperature class T5.

Other Warnings

Handling Precautions:

• WARNING: Potential electrostatic charging hazard. Electrostatic charge may cause an explosion hazard. Avoid actions that generate electrostatic charge, e.g., rubbing with a dry cloth.
• Sensors with a titanium (-TN) solution ground tip exclude ignition sources due to impact and friction sparks.
• IEC60079-14 requires a label indicating 'simple apparatus'. Stick this label to the sensor if necessary.

After-sales Warranty

• Do not modify the product.
• For repairs under warranty, contact the local sales representative or service office. Yokogawa will replace or repair damaged parts. Provide model name, serial number, and a description of the problem, including diagrams or data if possible.
• A repair report will not be provided if the product is replaced with a new one.
• Yokogawa warrants the product for the period stated in the pre-purchase quotation. Warranty service is based on Yokogawa's standard. A dispatch fee for the maintenance engineer will be charged if the customer site is outside the service area.

Cases Charged Repair Fee Regardless of Warranty Period:

• Failure of components out of warranty scope.
• Failure caused by usage of software, hardware, or auxiliary equipment not supplied by Yokogawa Electric.
• Failure due to improper or insufficient maintenance by the user.
• Failure due to modification, misuse, or operation outside specifications not authorized by Yokogawa.
• Failure due to abnormal or out-of-specification power supply (voltage, frequency).
• Failure caused by usage outside recommended usage scope.
• Damage from fire, earthquake, storms, floods, lightning, riots, warfare, radiation, or other natural changes.

• Yokogawa does not warrant conformance with specific applications at the user site and will not bear responsibility for damage due to specific applications.
• Yokogawa Electric will not bear responsibility when the user configures the product into systems or resells it.
• Maintenance service and repair parts supply are covered for five years after production ends. Contact the nearest sales office for repairs.

Specification

Standard Specifications

• Measurement: Hydrogen ion concentration (pH) of a solution.
• Measurement principle: Glass electrode method.
• Measuring range: 0 to 14 pH (see Table 1).
• Installation: Mounting in PH8HS submersion holder, PH8HG guide-pipe holder, or PH8HF flow-through holder.

Note: For the following solutions, install the sensor in a flow-through or submersion holder:

• Solution temperature exceeds 80°C.
• pH of the solution is 2 or less, or 12 or greater.
• Measurement of strong acid solutions (e.g., aqua regia, chromic acid, hypochlorous acid, perchloric acid).
• Solution contains corrosive gases (e.g., ammonia, chlorine, hydrogen sulfide).
• Solution contains a small percentage of organic solvent or oil.

• Solution temperature: -5 to 105°C (when mounted in PH8HG guide-pipe holder: -5 to 80°C; when mounted in PH8HS, PH8HF holder, see Table 1).

Table 1. Process Temperature Range

Notes:

• PVC: Rigid Polyvinyl, PP: Polypropylene, SS: Stainless Steel.
• Stainless steel holder and Stainless steel adapter should be used when the pH value of the solution is pH3 or more acidic.
• For flow-through types, refer also to the solution temperature and pressure graph (in notes following Model and Suffix code table for flow-through type holders).
• The temperature of chemical cleaning is 0 to 50 °C.
• Cannot be used with pH sensors connected to Variopin connector.

Table 2. Process Pressure Range

*1: For flow-through types, refer also to the solution temperature and pressure diagram of Holder IM.

*2: When general purpose reserve tank used.

*3: When medium-pressure reserve tank used.

• Operating solution depth: 3 m water pressure (max.) under atmospheric pressure.
• Solution flow velocity: 2 m/s max.
• Solution flow rate: 3 to 11 L/min (when the sensor is installed in a flow-through type holder).
• Solution conductivity: 50 µS/cm or higher.
• Wetted part materials: Body: Ryton (PPS resin), Glass, Titanium or Hastelloy C, Ceramics or Fluoropolymer (PTFE), Fluoro rubber (FKM) rubber or Perfluoroelastomer (FFKM). Cable: Chlorinated polyethylene rubber (Cable sheath).
• KCI solution supply tube: Heat-resistant soft PVC (General purpose or big volume tank 500 mL), Polyethylene (Medium pressure).
• Weight: Sensor: Approx. 0.4 kg. KCI Tank: Approx. 0.3 kg (General purpose), Approx. 1 kg (Medium pressure), Approx. 0.8 kg (Big volume).
• KCI solution consumption: when pressurized with 10 kPa. Maximum 3 mL/day (general junction), Maximum 20 mL/day (PTFE junction).
• Output Response: Response time (for 90% response); 10 seconds maximum (when the sensor, stabilized at 20°C, measures a solution at 20°C).

CAUTION: Select the material of wetted parts with careful consideration of process characteristics. Inappropriate selection may cause leakage of process fluids, which greatly affects facilities. Considerable care must be taken particularly in the case of strongly corrosive process fluid such as hydrochloric acid, sulfuric acid, hydrogen sulfide, and sodium hypochlorite. If you have any questions about the wetted part construction of the product, be sure to contact Yokogawa.

Model and Suffix Codes

pH Sensor

*1: 2-inch pipe mounting bracket is supplied with TT1, TT2 and TT3.

*2: Only a supply tube, but no KCI solution, is supplied with TN1 and TN2. Since a KCI solution is not supplied with TT2, arrange it from among accessories or auxiliary parts.

*3: Prepare an air pressure regulator as shown in the diagram below when the medium-pressure reserve tank is used.

*4: Mark band is shown by alphanumeric and fork terminals are used.

*5: Mark band is shown by numeral and pin terminals are used. When terminal box is used, select WTB10-PH1.

*6: The tag which indicated the color, the sign, and the number is attached to the cable of a sensor.

*7: Choose Perfluoroelastomer (FFKM) when this is used in organic solvent, high temperature alkaline solution.

*8: Choose when using in high alkali or high temperature alkaline solution.

*9: Choose when using in the heavily contaminated application.

*10: Mark band is shown by numeral and M3 ring terminals are used. When terminal box is used, select WTB10-PH3.

*11: Mark band is shown by numeral and M4 ring terminals are used. When terminal box is used, select WTB10-PH5.

*12: Option /K (with certificate of measurement law of Japan) cannot be specified. Do not allow the part above the sensor flange to contact with the solution.

Accessories

*1: Including the following: Two 200 mL polyethylene cups, One cleaning bottle.

*2: Either /KCLL or /KCLP is required for PH8EFP---TT2.

Consumables

Note: The pH value of the calibrating buffer solution may vary depending on storage conditions. Prepare a new solution from powder for accurate instrument calibration.

External Dimensions

Dimensions are in mm.

For FLXA202, FLXA21 (PH8EFP-□□-□□-TT-N-F*A)

For FLXA402, PH450, PH202/TB (PH8EFP---TT-N-G*A)

Ring terminals (-F, -G)

Sensor cable

Connector for KCI reserve tank

KCI solution tube

Tube length (Standard: 3m, 5m, 7m, 15m, 20m)

Pin terminal (-E)

For PH200, PH400 (PH8EFP-□-□□-TT-N-T*A)

For PH100 (PH8EFP-□□-□□-TT-N-B*A)

Fork terminal (-T, -B)

Variopin connector (PH8EFP-V--T-N-V*A)

KCI solution tube

Tube length (Standard: 3m, 5m, 7m, 15m, 20m)

Figure 1.1 PH8EFP Filling type pH Sensor

KCI Reserve Tanks

General Purpose KCI Reserve Tank (PH8EFP - □□ - □□ - TT1 - □ - *A)

Approx. 151 (Height), Ø63 (Diameter)

JIS 50A pipe (O.D.: Ø60.5)

Approx. 75, Approx. 45 (Dimensions)

Weight: Approx. 0.3 kg

General Purpose KCI Reserve Tank (500 mL) (PH8EFP - □□-□- TT3 - □ - *A)

Approx. 151 (Height), Ø105 (Diameter)

JIS 50A pipe (O.D.: Ø60.5)

Approx. 60, 25, 60 (Dimensions)

Weight: Approx. 0.8 kg

Midium Pressure KCI Reserve Tank (PH8EFP - □□ - □□ - TT2 - □ - *A)

68, 263, 308 (Dimensions)

Pressure gauge, Socket type connector, Rc1/4 screw

JIS 50A pipe (O.D.: Ø60.5)

Weight: Approx. 1 kg

Holes Dimension for Wall Mounting: 70±0.2

Installation

Preparation for Installation

Unpacking and Inspection

The PH8EFP pH sensor is well packed to prevent shipping damage. After removing from the shipping container, visually check the sensor for damage. Verify the order details against the information on the nameplate attached to the sensor body or sensor cables.

NOTE:

• The "glass electrode" and "liquid junction" are packed separately from the sensor body.
• DO NOT remove the caps of the "glass electrode" or pull the "glass liquid junction" out of the package until ready for use to prevent drying.

Figure 2.1 An Example of Model Number Entering to Nameplate

Figure 2.2 Names of PH8EFP pH Sensor Components

Mounting Glass Electrode

Mount the glass electrode on the sensor body as follows:

1. Peel off the seal from the electrode mounting hole on the sensor body.
2. Remove the cap for the glass membrane. Wipe off any solution on the O-ring with a tissue.
3. Remove the cap for the gold-plated pin.
4. Confirm that the O-ring is not damaged and will seal properly.
5. Mount the glass electrode on the sensor body. Insert the electrode into the mounting hole and screw clockwise until the O-ring fits tightly.

NOTE:

• The cap for the glass membrane contains solution to keep it wet (pH4 buffer solution). Do not splash the solution when removing the cap. Handle carefully as the rod beside the glass membrane is fragile.
• Before mounting, ensure the O-ring and gold-plated pin are not wet. Wipe off any remaining solution.
• Ensure there are no droplets in the mounting hole, as this may cause insulation failure.
• Use the electrode within one year of purchase. For best results, place the glass electrode in pH4 or pH7 buffer solution for more than a day before use.

Mounting Liquid Junction

The liquid junction is mounted in the sensor body when the KCl solution is poured into the sensor body. Refer to Section 2.2.

Installing Holder

Usually, the pH sensor is suspended in a guide pipe or installed in a flow-through or submersion holder. Install the holder first.

Installing Associated Instruments

Ensure the associated instrument (pH transmitter/converter or junction terminal box) to which the pH sensor cable is connected is already installed.

Requirements for mounting the pH sensor

In case of installing the PH8HG Guide-pipe Holder

To install the sensor in the guide pipe:

1. Connect the sensor cable to the associated instrument, referring to Section 2.3.
2. Mount the liquid junction in the sensor body. Peel off the seal and screw the liquid junction gently into the mounting hole.
3. If specified, attach the reserve tank (containing 250 mL KCl solution) to the pipe (nominal diameter 50 mm). Connect the reserve tank to the KCl solution supply tube of the sensor. Remove the tank cap and securely screw the tube connector into the tank.
4. Supply KCl solution to the sensor (see Figure 2.3). Mount the reserve tank with the tube connection facing downwards. Make several holes in the top of the tank using the supplied pin. Stand the sensor upside down, lower than the reserve tank, so that KCl solution flows from the tank into the sensor. When the sensor fills and overflows from the liquid junction mounting hole, securely screw the liquid junction into place.

Figure 2.3 Supplying KCI Solution to Sensor Body

For the Big-volume reserve tank, refer to pages 2-9 to 2-10.

5. Attach the "stopper" supplied with the guide pipe to the sensor cable.
6. Fix the sensor cable so that the sensor tip projects 20 to 30 mm from the pipe end when the pH sensor is suspended in the guide pipe (Figure 2.4).

NOTE: If the sensor tip does not project out from the pipe end, the measured value may not respond promptly to pH variations. If the tip projects too far, the sensor may be damaged by scraping against the pipe.

Figure 2.4 Mounting Sensor in Guide Pipe

Installing Sensor in PH8HS Submersion Holder

To install the sensor in the submersion holder:

1. Pass the sensor cable through the sensor holder. If the submersion holder is installed, remove the sensor holder.

For pipe-mounting submersion holder without a cleaner: Loosen the sensor holder nut to remove the holder.

Figure 2.5 Removal of Sensor Holder (Arm Pipe used with option /MS1 or /MS2)

Figure 2.5 Removal of Sensor Holder (Stainless Bracket used with option /MS3 or /MS4)

For flange mounting submersion holder without a cleaner: Loosen the two bolts securing the sensor holder to the flange and remove the sensor holder (Figure 2.6).

Figure 2.6 Removal of Sensor Holder (for Flange Mounting Sensor without Cleaners)

2. Remove the protector screwed onto the sensor holder end and then remove the protective foam piece (for shipping). Pass the sensor cable through the O-ring, then attach the O-ring to the sensor flange (Figure 2.7).

Figure 2.7 Removal of Sensor Holder (with Cleaner)

When passing the sensor cable through the holder, if the inside is dirty or wet, keep the cable dry by covering the sensor cable end with a polyethylene bag. Pull out the sensor cable and KCI solution supply tube downward through the holes of the Waterproof Cap (Figure 2.8).

For details on installing the sensor onto a holder, refer to relevant User's Manuals.

When a Variopin connector is attached to a sensor, connect the sensor to SA11 and WU11 cable first, then insert the sensor into the holder pipe. For sensor connection details, read IM 12A06S01-00EN-(P), IM 12A06S01-01Z1-(P).

CAUTION: Hold the upper part of the sensor when screwing a Variopin connector into it. Holding the lower part may apply excessive force and damage the sensor.

Figure 2.8 Installing the Sensor Cable

Installing Sensor in Flow-through Holder

To install the sensor in a flow-through holder:

1. Connect the sensor cable to the associated instrument. First, remove the sensor fixing nut and pass the sensor cable through the nut.

Figure 2.10 Preparation for Sensor Cable Connection

Connect the sensor cable properly by referring to Section 2.3.

2. Mount the liquid junction on the sensor body. Peel off the seal covering the liquid junction mounting hole and screw the liquid junction softly into the hole for two or three turns.
3. If specified, attach the mounting hardware for the general purpose reserve tank to a pipe (2-inch). Connect the general purpose reserve tank to the KCI solution supply tube of the sensor. Remove the tank cap and screw the tube connector securely into the tank.

When using a medium pressure reserve tank, attach it to a pipe (2-inch) and perform air piping to supply pressure for the reserve tank (Figure 2.11). Connect the KCI supply tube of the sensor to this reserve tank.

Figure 2.11 Air Piping for Pressurizing Medium Pressure Reserve Tank

3. Supply KCl solution to the sensor.

• When a general purpose reserve tank is used: Mount the reserve tank on the holding hardware with the tube connection part directed downwards. Make several holes in its top using the supplied pin (see Figure 2.3). Stand the sensor upside down, lower than the reserve tank, so that KCl solution flows from the tank into the sensor. When the sensor fills and overflows from the liquid junction mounting hole, securely screw the liquid junction into place.
• When a reserve tank for medium pressure is used: Fill the reserve tank with KCl solution (*1). Loosen the nut on the reserve tank upside and remove the cap. Pour approximately 250 mL of KCl solution into the tank. Stand the sensor upside down, lower than the reserve tank, so that solution flows from the tank into the sensor. When the sensor fills and overflows from the liquid junction mounting hole, securely screw the liquid junction into place. Remount the cap and tighten the nut securely.

*1: Use 3.3 mol/L KCl solution. If KCl powder (ordered separately) is supplied with the PH8AX accessories, dissolve one bag (60 g) of KCl powder in pure water to make exactly 250 mL of solution.

• When a Big-volume reserve tank is used: Fill the reserve tank with KCl solution. Loosen and remove the top cover and pour approximately 500 mL of KCl solution. Handle the cover carefully when loosening or closing. Do not overtighten the fixing nut at the bottom of the reserve tank, as this may cause cracks and leakage, leading to unstable readings or measurement errors.

Figure 2.11.1 Big-Volume Reserve Tank

4. Connect the pH sensor to its holder. Remove the protective cap from the sensor and the protective foam piece (for shipping). Ensure the liquid junction and glass electrode are mounted properly. Insert the sensor tip into the holder and tighten the sensor fixing nut securely (see Figure 2.10).

When a Variopin connector is attached to a sensor, connect the sensor to SA11 and WU11 cable first, then insert the sensor into the holder pipe. For sensor connection details, read IM 12A01F01-02EN.

CAUTION: Hold the upper part of the sensor when screwing a Variopin connector into it. Holding the lower part may apply excessive force and damage the sensor.

Figure 2.12 Installing Sensor in Flow-through Holder

For installation of HH350G, PB350G, and PB360G holders, refer to relevant IMs.

pH Sensor Cable Wiring Procedure

Processing of Cable Inlet Hole

Open the cable inlet hole in the terminal box using the supplied punch tool. The hole location is indicated by a circle-shaped groove under the case. Insert the punch tool into the center of the circle and tap with appropriate force to punch out the hole along the groove.

Figure 2.13 How to punch out the wiring hole

Connecting Sensor Cable

1. Loosen the two screws on the front of the terminal box and detach the cover.
2. After detaching the nut from the sensor cable's cable gland, pull the cable into the terminal box from the sensor cable inlet hole.
3. Connect the sensor cable to the terminals. After passing the cable through the nut, check the symbol on each core wire and connect each core wire to the corresponding terminal.

Figure 2.14 Connecting Sensor Cable (In case of the PH8TBG)

4. Mount the cable gland in the cable inlet hole.

Put the nut in place and screw it onto the main body sufficiently. Loosen the cap so that the cable is not twisted. After fixing the main body, tighten the cap to keep moisture out of the equipment. Overtightening the cap may damage the cable.

Figure 2.15 Cable Gland

After completing the cable connections, replace the box cover securely to prevent moisture from entering the case.

Connecting Sensor Cable to FLXA202/FLXA21

For the FLXA202/FLXA21 2-Wire Analyzer, refer to IM 12A01A02-12E or IM 12A01A02-01E.

Connecting Sensor Cable to Two-wire pH Transmitter

To connect the sensor cable to the two-wire pH transmitter:

1. Loosen the four screws that tighten the transmitter cover and remove the cover.
2. Connect the sensor cables to the relevant terminals of the transmitter. Remove the nut from the cable gland. Insert the cable into the right opening for wiring. Connect the individual cable conductors to the relevant terminals correctly by referring to the markings on the individual conductors.

Figure 2.16 Connecting Sensor Cable to Two-wire pH Transmitter

Install the cable gland in the wiring hole as follows:

Pass the tip of the cable gland into the opening and completely tighten the gland with the nut inside the case. After tightening the gland, secure the cap properly to prevent moisture from getting into the case.

Caution: Do not overtighten the cap. Otherwise, the cable may be damaged.

After completing the cable connections, replace the transmitter cover securely, thus preventing moisture from getting into the case.

Connecting Sensor Cable to FLXA402

For the connection to FLXA402 4-Wire Converter, read the user's manual IM 12A01F01-02EN.

Installing Sensor in Submersion Holder

Figure 2.9 Installing Sensor in Submersion Holder

Close the waterproof cap, and attach the holder to the arm pipe, flange or cleaner holder completely.

Maintenance on Operation

Operation and Periodic Maintenance

Calibrating pH Sensor Using Buffer Solutions

Calibrate pH sensors with buffer solutions before starting normal operation, as the emf of glass electrodes differs. The emf of a glass electrode gradually changes due to electrode staining or deterioration. Therefore, periodic calibration is necessary to keep measurement errors within specified limits.

For detailed calibration procedures, see relevant pH transmitter/converter IMs.

Pressurizing Reserve Tank

When using a medium pressure reserve tank, apply air pressure to the reserve tank before flowing the measured solution through the holder. Set the air pressure slightly higher than the maximum pressure of the measured solution during operation.

The flow rate of KCl solution from the liquid junction is maximum 3 mL/day for a general junction and maximum 20 mL/day for a PTFE junction. The flow rate increases in proportion to the pressure difference between air and the measured solution. To minimize KCl solution consumption, minimize pressure variations of the measured solution and ensure the air pressure is not set too high.

Replenishment of KCI Solution

When the KCl solution in a general type reserve tank is nearly exhausted, replace the tank with a new one (provided separately as a spare part).

For replenishment, use a 3.3 mol/L solution prepared by dissolving 246 g of KCl powder in pure water to make exactly one liter of solution. When pouring the solution into the tank, be careful not to let KCl solution overflow from the vent holes.

For a medium pressure reserve tank, replenish the KCl solution when it seems nearly exhausted. Perform replenishment as follows:

1. Close the valves to shut off the flow of measured solution (Figure 3.1) - first the inlet, then the outlet valves in the flow-through type holder.

Figure 3.1 Process Piping of Flow-through Type Holder.

2. Remove the socket connector on the reserve tank and stop the air pressurizing (Figure 3.2).

Figure 3.2 Socket Type Connector.

3. Remove the nut fixing the reserve tank cap and remove the cap.
4. Refill the tank with 3.3 mol/l KCl solution (Figure 3.3). The maximum solution level should be 30 to 40 mm below the top.

Figure 3.3 Maximum KCI Replenishment Level

5. Retighten the nut to fix the cap in position.
6. Open the valve and let the measured solution flow through the holder.

Cleaning Glass Electrode and Liquid Junction

Staining of the glass electrode or liquid junction can cause measurement errors. If the measured solutions tend to stain the electrode, clean the glass electrode and liquid junction periodically, depending on the degree of staining. If the pH sensor is installed in a holder with a cleaner, it is cleaned automatically.

Sensor cleaning is not usually required. However, if sensor characteristics are affected by chemical staining (e.g., when used for pH measurement of highly alkaline solutions), perform acid washing.

To clean the glass electrode or liquid junction:

• Stains due to suspended Solids, Sticky Materials, Microbes or the like: Wipe the stains off the glass electrode or liquid junction with soft tissue paper. Rinse off any remaining stains with water.
• Stains due to Oily Materials: Wash off stains by submerging in a neutral detergent solution in a beaker for several tens of minutes to several hours, depending on the degree of staining.
• Chemical Stains such as due to Metallic Adsorption: Place the glass electrode or liquid junction in a diluted hydrochloric acid solution (1 to 2%) for several minutes (acid washing).

Replacing Consumable Parts

Replacing Glass Electrode

If buffer solution calibration becomes impossible due to deterioration of the glass electrode, replace it with a new one. Always perform buffer solution calibration after replacing the glass electrode.

Replacing Liquid Junction

If normal measurement cannot be made even after washing the liquid junction, replace the liquid junction.

When replacing the liquid junction, fill the sensor with KCl solution to just before the solution overflows through the liquid junction mounting hole. Use a 3.3 mol/L KCl solution (a higher concentration of KCl or KCl powder) for this application.

Figure 3.4 Replacing Liquid Junction

Replacing O-rings for Glass Electrode

The inside of the glass electrode mounting hole requires high insulation resistance. Fluorocarbon rubber O-rings with superior chemical and heat resistance are used for sealing. Except for special uses, this O-ring does not need individual replacement. If any damage that might cause problems is detected in the O-ring, replace it along with the glass electrode.

Although the O-ring can be replaced individually if it deteriorates faster than the glass electrode, it is recommended to replace the whole glass electrode to avoid possible deterioration of the O-ring inside the glass electrode. For individual replacement of the O-ring, use the one recommended by Yokogawa.

When installing the O-ring, wind a slip of paper or tape around the thread part on the glass electrode to prevent scratching the O-ring. Scratches may damage its sealing properties.

For ordering, refer to the Customer Maintenance Parts List (CMPL) at the end of the book to check the appropriate part number of the O-ring.

Figure 3.5 Installing the O-ring

Customer Maintenance Parts List

Model PH8EFP KCI Filling type pH Sensor

Figure: Exploded view of PH8EFP pH Sensor and related parts

Medium Pressure KCI Reserve Tank Assembly for Suffix Code: -TT2 (K9142VG)

Item | Part No. | Qty | Description

1 | K9142VL | 1 | Tank Assembly

2 | K9142VJ | 1 | Block

3 | K9142VK | 1 | Block

4 | G9303AE | 1 | O-Ring

6 | L9835DD | 1 | Joint

7 | L9867BS | 1 | Pressure Gauge

8 | K9142RU | 1 | Label

9 | K9142VP | 1 | Bracket

10 | K9142EJ | 1 | Cap

11 | K9142VQ | 1 | Ring

12 | L9826AL | 1 | Bracket

13 | D0117XL-A | 1 | U-Bolt

Revision Information

• Title: Model PH8EFP KCI Filling type pH Sensor
• Manual No.: IM 12B7J1-01E
• Feb. 2020/14th Edition: Added terminal connection to -E: FLXA402 to Pin terminal (P.1-3, 1-5). Corrected an error on the dimension (P.1-5).
• Mar. 2019/13th Edition: Corrected errors (P. i, 1-3, 2-1, 2-6, 2-10).
• Dec. 2018/12th Edition: Added -V (Variopin connector) (Pi, P1-1, 1-3, 1-5, 1-6, 2-1, 2-6, 2-10, 2-13, CMPL).
• Nov. 2018/11th Edition: Added FLXA402 (Pi, P1-3).
• Jan. 2016/10th Edition: Change of KCI solution consumption (P1-2, P3-1). Unification of material name, and added connecting Sensor Cable to FLXA202/FLXA21 (P1-2, P1-3, P1-4, P2-12, P3-1).
• Oct. 2015/9th Edition: Added FLXA202 (Pi, P1-1, P1-2, P1-3). Unification of material name (P1-1, P1-2, P1-3).
• Jul. 2015/8th Edition: Page ii to iii: Added a postscript about Compliance with the simple apparatus requirements. CMPL 12B05J01-02E revised to 11th edition.
• Jun. 2013/7th Edition: Page 2-1 to 2-2: Revision of Sec. 2.1.1 and 2.1.2 (addition of the cap to keep the glass electrode wet). Page 3-1 to 3-4: Deletion of Sec. 3.1.1 (how to keep the glass electrode wet moved to Sec. 2.1.2) and following section no. and page layout changed. CMPL 12B05J01-02E revised to 10th edition, because some P/N addition of O-ring for /PF option.
• Jul. 2011/6th Edition: Page layout changed by InDesign. Page i: Reference manual number of FLXA21 added. Page 1-3: M4 ring terminals for FLXA21 added to MS-code. Page 1-5: M4 ring terminals added to external dimensions. CMPL 12B05J01-02E revised to 9th edition (Note for 500 ml KCl tank modified).
• Mar. 2010/5th Edition: Page 3-1 to 3-3: Section 3.1.1 changed to "Advance Preparation", section order changed. Some of Section 3.2.1 "Replacing Glass Electrode" modified. Page 3-4: Changing page of Section 3.2.3 "Replacing O-rings for Glass Electrode.". CMPL 12B05J01-02E revised to 8th edition.
• Apr. 2008/4th Edition: M3 ring terminals added for PH450G, CMPL12B05J01-02E revised to 7th edition.
• Jul. 2006/3rd Edition: All over revised.
• Feb. 1996/2nd Edition: Some error corrected.
• Dec. 1995/1st Edition: Newly published.

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