OPERATING INSTRUCTION MANUAL

Transcription

1 OPERATING INSTRUCTION MANUAL High Purity Water ph Sensor System Worldwide Sales: GLI International, Inc West Dean Road Milwaukee, Wisconsin 53224, U.S.A. phone: [414] fax: [414] European Sales: GLI International Ltd Eastman Way, Hemel Hempstead Hertfordshire. HP2 7HB England phone: fax: In the interest of improving and updating its equipment, GLI reserves the right to alter specifications to equipment at any time. A Member of the Environmental Instrumentation Group 1 High Purity Water ph Sensor System

2 HELPFUL IDENTIFIERS In addition to information on installation and operation, this instruction manual may contain WARNINGS pertaining to user safety, CAUTIONS regarding possible sensor malfunction, and NOTES on important, useful operating guidelines. WARNING: A WARNING LOOKS LIKE THIS. ITS PURPOSE IS TO WARN YOU OF THE POTENTIAL FOR PERSONAL INJURY. CAUTION: A CAUTION LOOKS LIKE THIS. ITS PURPOSE IS TO ALERT YOU TO POSSIBLE SENSOR MALFUNCTION OR DAMAGE. NOTE: A note looks like this. Its purpose is to alert you to important operating information. High Purity Water ph Sensor System 2

3 TABLE OF CONTENTS PART ONE - INTRODUCTION SECTION 1 GENERAL INFORMATION 1.1 Description Operating Precautions SECTION 2 SPECIFICATIONS... 6 PART TWO - INSTALLATION SECTION 1 LOCATION REQUIREMENTS... 7 SECTION 2 MOUNTING PART THREE - SERVICE AND MAINTENANCE SECTION 1 RECOMMENDED CLEANING PROCEDURE SECTION 2 SECTION 3 REPLACING STANDARD CELL BUFFER AND SALT BRIDGE TROUBLESHOOTING 3.1 Operating Test Customer Assistance PART FOUR - SPARE PARTS AND ACCESSORIES High Purity Water ph Sensor System

4 TABLE OF CONTENTS (continued) ILLUSTRATIONS Figure 2-1 Mounting Details... 8 Figure 3-1 Sensor Electrode Details MONTH GLI DIFFERENTIAL SENSOR WARRANTY/REPLACEMENT PLAN GLI International, Inc. will replace or repair any GLI Differential Sensor that fails due to defects in material or workmanship for a period of up to 12 months from the date of shipment from our facility. In this case, the following condition applies: 0-12 months old...sensor is replaced free If the sensor fails -- for any reason -- within the 30 months from the date of shipment, it will be replaced at the following prorated pricing: 0-18 months old...sensor is replaced at approximately 1/3 of current list price months old...sensor is replaced at approximately 2/3 of current list price Each sensor is identified with a unique serial number that is used by GLI International, Inc. to validate the month and year of shipment. A warranty claim will not be honored if defects are not reported within the warranty period, or if GLI International determines that defects or damages are due to normal wear, misapplication, lack of maintenance, abuse, improper installation, alteration, or abnormal conditions. GLI International s obligation under this warranty shall be limited to, at its option, replacement or repair of this product. The product must be returned to GLI International, freight prepaid, for examination. The product must be thoroughly cleaned and any process chemicals removed before it will be accepted for replacement or repair. GLI International s liability shall not exceed the cost of the product. Under no circumstances will GLI International be liable for any incidental or consequential damages, whether to person or property. GLI International will not be liable for any other loss, damage or expense of any kind, including loss of profits, resulting from the installation, use, or inability to use this product. High Purity Water ph Sensor System 4

5 PART ONE - INTRODUCTION SECTION 1 - GENERAL INFORMATION PART ONE - INTRODUCTION SECTION 1 GENERAL INFORMATION 1.1 Description This ph sensor assembly is specifically engineered for high purity water applications in solution conductivities as low as µs/cm (18.2 megohm cm). Its superior design: Enables the use of equi-transferant buffer and salt bridge solutions, eliminating the ± 0.2 ph unit error associated with typical KCl-based reference electrodes. Eliminates maintenance problems of flowing junctiontype reference electrodes. Eliminates the need to use special calibration buffers. The complete stainless steel sensor assembly includes an integral flow-through chamber with a quick-disconnect mount, and a convenient bracket to surface or pipe mount the assembly. The sensor electronics are encapsulated within in a stainless steel housing to avoid problems caused by electrical interference, moisture, and high humidity. The sensor body is made of pure PVDF to withstand the demands of ph measurement in pure water. The sensor measures ph using the GLI Differential Electrode Measurement Technique. This field-proven technique uses three electrodes instead of the two normally used in conventional ph sensors. Process and reference electrodes measure the ph differentially with respect to a third ground electrode. The end result is unsurpassed measurement accuracy, reduced reference junction potential, and elimination of sensor ground loops. This sensor provides greater reliability, resulting in less downtime and maintenance. This high purity water ph sensor has an integral PT 1000 ohm RTD temperature element to automatically compensate ph readings for temperature changes. 1.2 Operating Precautions 1. Before placing the sensor into operation, remove the protective plastic caps to expose the process electrode 5 High Purity Water ph Sensor System

6 PART ONE - INTRODUCTION SECTION 2 - SPECIFICATIONS and salt bridge (shown in Figure 3-1). Save the caps for future use. NOTE: If the sensor will be out of solution for more than an hour or two, put a few drops of water in each cap and place them back onto the process electrode and salt bridge. This keeps these components moist and avoids slow response when the sensor is put back into operation. Depending on the environmental conditions, do this every 2 to 4 weeks for extended storage. 2. The process electrode at the tip of the sensor has a glass bulb which can easily break. Do not subject it to impact or other mechanical abuse. CAUTION: IF THE SENSOR PROCESS ELECTRODE BREAKS, HANDLE THE SENSOR CAREFULLY TO PREVENT SERIOUS CUTS. SECTION 2 SPECIFICATIONS Wetted Materials...PVDF sensor body, LCP salt bridge with PVDF junction, glass process electrode, titanium ground electrode, and Viton O-ring process seals; integral 316 stainless steel flow-through chamber with Viton gasket Temperature Range C ( F) Maximum Pressure...60 psi Flow Rate milliliters per minute (less than 100 milliliters per minute for best accuracy) Measuring Range...2 to 12 ph Process Connection...1/4-inch female NPT Stability ph per 24 hours, non-cumulative Sensitivity ph in solution conductivities as low as µs/cm (18.2 MΩ cm) Temperature Element...Integral PT 1000 ohm RTD Sensor Cable...5 conductors (plus shield); 10 ft. (3 m) long Transmission Distance ft. (914 m) maximum High Purity Water ph Sensor System 6

7 PART TWO - INSTALLATION SECTION 1 - LOCATION REQUIREMENTS PART TWO - INSTALLATION SECTION 1 LOCATION REQUIREMENTS Mount the sensor vertically with electrodes pointing downward. If the sensor must be installed on an angle, it should be at least 15 above horizontal. Other mounting angles may cause erratic measurement readings. SECTION 2 MOUNTING The high purity water ph sensor assembly may be mounted onto any flat surface or, by using a U-bolt and hex nuts (supplied by user), onto a horizontal or vertical pipe. The complete assembly consists of the flanged sensor secured into a stainless steel flow chamber with a quickdisconnect clamp. A Viton gasket provides a leak-proof seal between the sensor flange and flow chamber. Refer to Figure 2-1 for mounting dimension details. 1. Remove the sensor from the flow chamber before mounting the chamber. Surface mount the flow chamber using 5/16-inch screws of appropriate length. (To mount the flow chamber onto a pipe, use an appropriately sized U-bolt and hex nuts.) 2. Tap a sample line into the process. Connect this sample line to the flow chamber s 1/4-inch female NPT inlet. Recommendation: To regulate the flow to the chamber, install a flow restriction valve and flowmeter upstream of the chamber in the sample line. NOTE: Regulate the flow rate to the chamber to between 5 and 250 ml/min. Outside of this range ph measurement readings will be inaccurate. Recommendation: For best accuracy limit the flow rate to less than 100 ml/min. 3. Connect a drain line from the chamber s 1/4-inch female outlet to drain. NOTE: Do not restrict flow in the drain line. This may increase pressure in the chamber, which can cause drain line clogging and, ultimately, sample line flow rate changes to the chamber. 7 High Purity Water ph Sensor System

8 PART TWO - INSTALLATION SECTION 2 - MOUNTING 4. Connect the sensor cable wires directly to the analyzer or indirectly using a junction box and interconnect cable. A. Direct Connection a. Route the sensor cable to the analyzer in 1/2-inch or larger metal conduit to protect it from moisture and mechanical damage. Install a watertight connector, such as a cable feed-through fitting or conduit hub, in the analyzer cable entry hole. b. Connect the sensor cable wires to the analyzer. Refer to the analyzer instruction manual for connection details. B. Indirect Connection with Junction Box a. Mount a junction box (with terminal strip) onto a flat surface such that its cover is removable after installation. b. Route the sensor cable to the junction box in 1/2- inch or larger metal conduit to protect it from moisture and mechanical damage. Install a watertight connector, such as a cable feed-through fitting or conduit hub, into the junction box cable entry hole. FIGURE 2-1 Mounting Details High Purity Water ph Sensor System 8

9 PART TWO - INSTALLATION SECTION 2 - MOUNTING c. Route an interconnect cable from the junction box to the analyzer in 1/2-inch or larger metal conduit. Install watertight connectors, such as cable feedthrough fittings or conduit hubs, at both ends of the cable. If the interconnect cable is too long, shorten it to a proper length to avoid potential electrical interference caused by inductive pickup. NOTE: Do not route the interconnect cable in any conduit containing AC power wiring ( electrical noise may interfere with the sensor signal). d. Connect the sensor and interconnect cable wires, by matching colors, to the terminal strip inside the junction box. Fasten the cover onto the junction box. NOTE: Keep the terminal strip inside the junction box dry to prevent problems caused by wet and/or corroded terminals. e. Connect the interconnect cable wires to the analyzer. Refer to the analyzer instruction manual for connection details. 5. After connecting the sensor to the analyzer, remove the protective plastic caps from the sensor and save them for future use. Before mounting the sensor into the chamber, calibrate the measuring system using the procedure in the analyzer instruction manual. 6. After calibration, place the O-ring into the groove on the flow chamber housing. Carefully insert the sensor into the chamber, making sure that the O-ring is properly seated into the mating groove on the sensor flange. 7. Gently rotate the sensor to align its label with the label on the flow chamber. This correctly positions the sensor s process electrode into the sample flow path. 8. Properly position the quick-disconnect clamp onto the sensor flange and flow chamber, and tighten it to secure the sensor and prevent leaking. This completes the mounting. 9 High Purity Water ph Sensor System

10 PART THREE - SERVICE AND MAINTENANCE SECTION 1 - RECOMMENDED CLEANING PROCEDURE PART THREE - SERVICE AND MAINTENANCE SECTION 1 RECOMMENDED CLEANING PROCEDURE Normally in a pure water system, cleaning is not necessary. However, due to operational conditions with boiler cleaning, DI bed regeneration, and other applications that, at times, could cause contaminants to enter the ph sensor flow chamber, the ph sensor may require cleaning. Should cleaning become necessary, use the following procedure. NOTE: The times and acid concentration stated in the following procedure are approximate, but should provide optimal performance from the ph measurement system in pure water applications. 1. Remove most contaminate buildup by carefully wiping the entire measuring end of the sensor (process electrode, salt bridge, and ground electrode) with a soft clean cloth. Then rinse the sensor with clean, warm water. 2. Prepare a mild soap solution. Use warm water and dishwashing detergent or other non-abrasive soaps that do not contain lanolin which will coat the glass process electrode and may affect sensor performance. 3. Soak the sensor for 2 to 3 minutes in the soap solution. 4. Use a soft cloth to scrub the entire measuring end of the sensor, thoroughly cleaning the electrode surfaces. If detergent solution cleaning cannot remove surface deposits, use hydrochloric acid in a 1N concentration to dissolve the deposits. Some stubborn coatings may require a different cleaning agent. For assistance in these difficult cases, contact the GLI Customer Service Department. WARNING: ACIDS ARE HAZARDOUS. ALWAYS WEAR APPRO- PRIATE EYE PROTECTION AND CLOTHING IN ACCORDANCE WITH MATERIAL SAFETY DATA SHEET RECOMMENDATIONS. Soak the sensor in 1N hydrochloric acid until the coating dissolves (usually less than 5 minutes). Rinse the High Purity Water ph Sensor System 10

11 PART THREE - SERVICE AND MAINTENANCE SECTION 1 - RECOMMENDED CLEANING PROCEDURE sensor with clean, warm water and then place the sensor back into the mild soap solution for 2 to 3 minutes to neutralize any remaining acid. 5. Remove the sensor from the soap solution, and rinse the sensor again in running, clean water for approximately 30 minutes. 6. Rinse the sensor several more times in pure water. 7. Re-install the sensor into the flow chamber and allow the sample to flow through the assembly for approximately 30 minutes to allow the sensor to stabilize. 8. Remove the sensor from the flow chamber and calibrate the measuring system. Refer to the analyzer instruction manual for details. If calibration cannot be attained, replace the sensor s standard cell buffer solution and salt bridge (see Section 2). If calibration is still not possible, test the sensor operation using the procedure in Part Three, Section Re-install the sensor into the flow chamber again and allow the sample to flow through the assembly for approximately 30 minutes to allow the sensor to stabilize. NOTE: Measured readings will be somewhat inaccurate while the sensor stabilizes during this period. The 30-minute stabilization time is approximate and, depending on the application, may vary. 11 High Purity Water ph Sensor System

12 PART THREE - SERVICE AND MAINTENANCE SECTION 2 - REPLACING STANDARD CELL BUFFER/SALT BRIDGE SECTION 2 REPLACING STANDARD CELL BUFFER/SALT BRIDGE If calibration cannot be attained after cleaning the sensor, refer to Figure 3-1 and replace the standard cell buffer solution in the sensor and the salt bridge: 1. Hold the sensor with its electrodes upright and remove the salt bridge by turning it counterclockwise. Take care not to damage the protruding process electrode. Properly discard the old salt bridge. 2. Replace the standard cell buffer in the sensor s internal chamber: A. Pour out the standard cell buffer solution, and thoroughly flush the chamber with clean water. B. Fill the chamber with fresh standard cell buffer solution (GLI part number 25M1A ). 3. Before installing the new salt bridge (GLI part number ), inspect the salt bridge O-rings for imperfections and replace them if necessary. Screw in the new salt bridge clockwise (right) until it is finger tight. Then tighten with pliers approximately 1/4 turn more. Do not overtighten! FIGURE 3-1 Sensor Electrode Details High Purity Water ph Sensor System 12

13 PART THREE - SERVICE AND MAINTENANCE SECTION 3 - TROUBLESHOOTING SECTION 3 TROUBLESHOOTING 3.1 Operating Test In all cases, clean the sensor using the procedure described in Part Three, Section 1. If the measuring system cannot be calibrated after cleaning, replace the standard cell buffer solution and salt bridge as described in Part Three, Section 2 and try calibrating again. If the measuring system still cannot be calibrated, perform the following sensor test to determine if the sensor is operating properly. The test requires a multimeter and two ph buffers (ph 7 and ph 4 or ph 10). 1. Disconnect the sensor s red, green, yellow, and black wires from the analyzer (or junction box, if using interconnect cable). 2. Place the sensor in a ph 7 buffer. Before continuing, allow the temperatures of the sensor and buffer solution to equalize to approximately 25 C (room temperature). 3. Verify that the sensor s temperature element (PT 1000 ohm RTD) is okay by measuring the resistance between the yellow and black wires. The reading should be between 1050 and 950 ohms at approximately 25 C. 4. Reconnect the yellow and black wires. 5. Connect the multimeter s (+) lead to the red wire and its (-) lead to the green wire. With the sensor in the ph 7 buffer solution, measure the DC millivolts. This sensor offset reading should be between -50 and +50 mv. If it is, the sensor is within factory-specified limits. Then write down the millivolt value for this reading and perform step 6. If not, discontinue this test and refer to the GLI warranty/replacement plan on page 4 for sensor replacement details. 6. With the multimeter connected the same, now rinse the sensor with water and place it in either ph 4 or ph 10 buffer. Before continuing, allow the temperatures of the sensor and buffer solution to equalize to approximately 25 C (room temperature). Now measure the sensor span reading: 13 High Purity Water ph Sensor System

14 PART THREE - SERVICE AND MAINTENANCE SECTION 3 - TROUBLESHOOTING A. Span Reading in ph 4 Buffer With the sensor in ph 4 buffer, the sensor span reading should be at least +160 mv more than the noted offset reading taken in step 5. Examples of typical readings are: Offset Reading (in ph 7 buffer) Span Reading (in ph 4 buffer) -50 mv +110 mv -25 mv +135 mv 0 mv +160 mv +25 mv +185 mv +50 mv +210 mv B. Span Reading in ph 10 Buffer With the sensor in ph 10 buffer, the sensor span reading should be at least -160 mv less than the noted offset reading taken in step 5. Examples of typical readings are: Offset Reading (in ph 7 buffer) Span Reading (in ph 10 buffer) -50 mv -210 mv -25 mv -185 mv 0 mv -160 mv +25 mv -135 mv +50 mv -110 mv If the span reading is at least +160 mv more than or -160 mv less than the offset reading with the sensor in ph 4 or ph 10 buffer respectively, the sensor is within factory-specified limits. If not, refer to the GLI warranty/ replacement plan on page 4 for sensor replacement details. This completes the sensor operating test. High Purity Water ph Sensor System 14

15 PART THREE - SERVICE AND MAINTENANCE SECTION 3 - TROUBLESHOOTING 3.2 Customer Assistance If you need assistance in troubleshooting or repair service, please contact your local GLI representative, or the GLI Customer Service Department at: GLI International, Inc. Telephone: [800] West Dean Road Fax: [414] Milwaukee, Wisconsin GLI SERVICE DEPARTMENT HOURS Monday through Thursday Friday Eastern Std. Time 8:30 a.m. to 5:30 p.m. 8:30 a.m. to 4:00 p.m. Central Std. Time 7:30 a.m. to 4:30 p.m. 7:30 a.m. to 3:00 p.m. Mountain Std. Time 6:30 a.m. to 3:30 p.m. 6:30 a.m. to 2:00 p.m. Pacific Std. Time 5:30 a.m. to 2:30 p.m. 5:30 a.m. to 1:00 p.m. All sensors returned for repair or replacement must be freight prepaid and include the following information: 1. A clearly written description of the malfunction. 2. Name of person to contact and the phone number where they can be reached. 3. Proper return address for shipping sensor(s) back. Include preferred shipping method (UPS, Federal Express, etc.) if applicable. 4. A purchase order if sensor(s) is out of warranty to cover costs of repair. NOTE: If the sensor is damaged during return shipment because of inadequate packaging, the customer is responsible for any resulting repair costs. (Recommendation: Use the original GLI shipping carton or an equivalent.) Also, GLI will not accept sensors returned for repair or replacement unless they are thoroughly cleaned and all process material is removed. 15 High Purity Water ph Sensor System

16 PART FOUR - SPARE PARTS AND ACCESSORIES PART FOUR - SPARE PARTS AND ACCESSORIES Description Part Number Sensor Accessories Spare ph Sensor P4 Flow Chamber Assembly... MH011A8S Spare Quick-disconnect Clamp... 9H1417 Spare Viton Gasket... 9H1384 Standard Cell Supplies Standard Cell Buffer (1 pint)... 25M1A Spare Salt Bridge (includes O-rings) XXX* *Substitute desired quantity of salt bridges for XXX suffix in part number. Example: Specify 001 for one salt bridge. Spare Viton O-rings for Salt Bridge: Large O-ring... 5H1016 Small O-ring... 5H1261 ph Buffer Solutions For Calibration and Operation Checks 1 pint of ph 7 Buffer... 99X3A pint of ph 4 Buffer... 99X3A pint of ph 10 Buffer... 99X3A0942 High Purity Water ph Sensor System 16