Dextens Electrochemical Oxygen Sensors Type 51100 Operating
Contents
1. 0 Dextens Electrochemical if Oxygen Sensors Type 51100 Operating Manual April 2012 Dextfens Table of Content 1 ee ae ee 4 1 1 DISC Eee ee a nee Een ee een oon ule ean selon A 1 2 SYMBOLS AND CONVENTIONS ccccceccccccccccecececececececececeuececucucucucucucacucucueueueueueceuuauacaceeueueaeceetaeaeauauavauauauauauauseeaenenss 4 1 3 SERVICES AND REPAIR Si ana a aan a dae A 1 4 BGE CON OY ne as ne Een are A 2 INDRODUCTION 222000000000a0 a0 anno nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nn nun nun un nun nn nun una nun 5 2 1 CONTENT OF PACKAGE OXYGEN SENSOR er can ala a en eu dee nennen 5 2 2 E 5 2 3 CONSUMABLES AND SPARE PARTS eher een 7 3 INSTALLATION errs 9 3 1 INTRODUCTION cccccccccccccecccececececececececucecucucueueueucucceueuuauceueegueeneneneueaucuaugucuneaeaenenenenenenenenenenenenecscseaeauaeeuauauauaeneass 9 3 2 SENSOR DIMENSION Se a es ee ee es Lee ee een 9 33 FLOW CHAMBER NSTALLAT ION 10 3 4 SENSOR SOCKET INSTALLATION Gstaad 11 3 5 INSERTION EXTRACTION VALVE INSTALLATION cececececececececccccaccecececenenenenenenuaeaenenenenenenenenenenensnstetetseecseececeneners 11 3 6 82400 F2. a span gas make sure the front end of the sensor is clean and dry 45 00 48 00 M 42X1 5 71 80 If you require a calibration gas and normal sample media to the flow chamber use one 3 way valve on each port Calibration gas is sent in through the sample out port and waste gas is sent out through the sample in port Back in normal operation right the calibration gas inlets and outlets are shut off Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland The flow chamber sensor assembly should be mounted either vertically or horizontally under the following conditions Smee Flow Chamber Orientation Gaseous or liquid Vertically Sensor uppermost Gaseous with Horizontally with outlet valve occasional liquid or under inlet to vapor allow for drainage aan Sample out Calibration gas in Sample in 10 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Installation 3 4 Sensor Socket Installation The model 74003 74004 sensor sockets are for sensor 61100 25mm and sensor 61101 28mm respectively The sensor socket enables the sensor to be installed into any stainless steel pipe with a diameter greater than 50mm The sensor extends 28 5mm into the sensor socket When cutting the sensor socket to fit the radius of your pipe you should allow for a 4mm setback between your pipe s inner diameter and the top of the sensor This will pr
3. follow the safety recommendations from this manual The material in this manual is for informational purposes only The products it describes are subject to change without prior notice due to the manufacturer s continuous development program Dextens makes no representations or warranties with respect to this manual and shall not be liable for any damages losses costs or expenses direct indirect or incidental consequential or special arising out of or related to the use of this manual All rights reserved No part of this manual may be used or reproduced in any form or by any means without prior written permission of Dextens 1 2 Symbols and Conventions The danger sign below indicates actions or configurations that may be dangerous for the user or that may lead to wrong measurements Read and understand these paragraphs before starting to use the described material 1 3 Services and Repairs No sensor components can be repaired by the user Only personnel from Dextens or its approved representative s is are authorized to attempt repairs to the sensor and only components formally approved by the manufacturer should be used Any attempt at repairing the sensor in contravention of these principles could cause damage to the sensor and corporal injury to the person carrying out the repair It renders the warranty null and void and could compromise the correct working of the sensor and the electrical integrity or the CE compliance of t
4. protective gloves and goggles Dextens SA 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 14 T 41 22 884 83 06 F 41223424860 info dextens ch www dextens ch Maintenance 4 4 Cleaning the Sensor 4 4 1 Dismantle the Sensor First remove the sensor from the measurement point please report to the related section in the paragraph 3 Then follow the explanation hereunder to dismantle the sensor When delivered a new sensor assembly looks as follows 1 Disconnect the various protective and support components by unscrewing them 2 Remove the locking screw with the removal tool 3 Remove the protective cap by pulling it off this will require some force If your sensor is fitted with a protective grid inside the protective cap do not discard it as it is often re useable If there is no protective grid there will be a seal this is also often re useable Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates m Switzerland 15 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance 4 Place the sensor in the sensor holder The small pin in the holder must fit into the exhaust hole in the reservoir Turn the sensor about 30 degrees clockwise to open the reservoir the hole and the mark must be aligned From this point you must take particular care because the electrolyte may leak from the reservoir Remark it is possible to unscrew the reservoir without this but ther
5. 0 to 150 having efficiencies from 90 to 110 is a sign of a good maintenance Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates m Switzerland 27 T 41 22 884 8306 F 41 22 342 48 60 info dextens ch www dextens ch 6 Testing 6 1 Introduction e Connect the sensor to an instrument e Check the speed and residual current of the sensor by performing a Sodium Sulfite test e The sensor should read less than 10 ppb within 10 minutes and less than 0 4 ppb within 60 minutes See trouble shooting if this performance is not achieved 6 2 Sodium sulfite test e Testing Dextens EC sensors performance and speed is done by connecting the sensor to an instrument process portable or package analyzer and plunging the sensor into a sodium sulfite solution The sodium sulfite solution has the effect of completely eliminating oxygen from the water e In order to complete this test you need to create the sodium sulfite solution Details of the sodium sulfite powder are provided below e Select a glass or beaker 250 ml is sufficient and add tap water to about 2 3 full Add 2 3 teaspoons of the sodium sulfite powder and stir for 20 30 seconds The concentration is correct if a small amount of powder remains un dissolved e Connect the sensor to an instrument and place it in the sodium sulfite solution After 10 minutes in the sulfite the reading must be less than 10ppb and after 1hour the reading should be lower than 1ppb e NOTE if there is
6. OR SENSOR IN LINE INSTALLATION ccccccccccccecececececececececececucucucucutececececececececucueacecueecueeteeauaveuauseauaeeees 12 4 MAINTENANCE 13 4 1 AR OM TON ae ea tee neces 13 4 2 WAEN TO CLEAN A S N OOR ae carers 13 4 3 MAINTENANCE TOOLS AND MATERIAL ccecececececcccccccccecccenecenenecececeueneneneneneneuenececeueueuacauauucaeacaceeacauaeuseteceuucacecaceees 14 4 4 CLEANING THE SENSOR see ce eee ee ee 15 CALIBRATION E EEEN 27 6 TESTING 28 6 1 INTRODEICTION E E E ae a ee A E E EEA E E EAE E A E 28 6 2 SODIUM S UL FITE TE T sees Scie 28 7 TROUBLE SOO PING 29 7 1 CALIBRATION OUTSIDE OF THE DEFINED RANGE cccccecececececececececececccecacauacauacucesueeeeeauauauauauauaeaeaeaeneneaeneneneneneneass 29 7 2 PUNCTURED MEMBRANE 2 2 en an han aan a a en 29 7 3 EMPTY ELECTROLYTE RESERVOIR ee a Reese nee 29 7 4 yoy eS Ore E 29 7 5 SLOW SENSOR 29 8 TECHNICAL SPECIFICATIONS an an an nam 30 Dextens SA 18 Chemin des Aulx 1218 Plan les Ouates m Switzerland 3 T 41 22 884 8306 F 41 22 342 48 60 info dextens ch www dextens ch 1 General Information 1 1 Disclaimer Please read and understand the user manual before installing and using the products described herein It is also recommended to
7. age applications 2 Clip the membrane frame on top of the reservoir Take care not to touch the membrane because it is very fragile 3 Clip the membrane frame on top of the reservoir Take care not to touch the membrane because it is very fragile Remark Make sure the reservoir is open 2 holes are aligned as shown on picture 4 Put about 5 drops of electrolyte on the membrane about 2 3 mm depth Inspect the electrolyte through a magnifying glass there should be NO bubbles in the electrolyte Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 23 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance 5 Carefully place 5 drops of electrolyte on the cathode and a few drops at the bottom of the anode It is important to make sure that the space between the cathode and guard is filled with electrolyte 6 Carefully and slowly screw the sensor into the reservoir this should be done with the reservoir OPEN the two holes should be aligned see section 3 3 Carefully inspect the membrane cathode and guard area with a magnifying glass to make sur that there are no air bubbles particularly between the cathode and guard Remark make sure the electrolyte reservoir is OPENED when you attach it to the sensor 7 Place the sensor in the holder The hole on the electrolyte reservoir A fits on the nipple of the holder B Fix the sensor by slightly screw
8. brane Expected Expected Minimum Maximum consumption current in air at current in pure expected current expected saturated water at 25 C 25 C oxygen in pure oxygen current in pure oxygen 82952A 5 4 27 pA 8 1 uA 45 9 pA 37 38 ug hour 82956A 26 4 pA 132 39 6 224 4 uA 1 193 ug hour 82958A 9 4 uA 47 WA 14 1 pA 79 9 3 59 ug hour Standard Sensor Cable Specifications Cable diameter 6 1 mm 0 3 mm 10 each stranded wires of 26 AWG individually insulated with polyethylene 90 shielded by tinned copper braid Resistivity 138 Q km Minimum bend radius 15 times cable diameter Dextens SA m 18 Chemin des Aulx m 1218 Plan les Ouates m Switzerland 30 T 41 22 884 8306 F 41 22 342 48 60 info dextens ch www dextens ch
9. e are more risks to damage the membrane 5 Unscrew the electrolyte reservoir Be careful with the electrolyte it is corrosive Wear protective gear 6 Unscrew the membrane lock 7 Remove the membrane frame You can either use a finger nail or the back side of a blade to lift the membrane frame Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 16 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance Upon disassembly the reservoir has the following components 4 4 2 Cleaning Methods There are two cleaning methods e Basic cleaning electrochemical cleaning to be performed about every 6 12 months depending on the application to ensure consistent readings from the sensor e Aggressive cleaning chemical cleaning this is an aggressive chemical cleaning This cleaning only needs to be performed in exceptional circumstances 4 4 3 Basic Cleaning The electrochemical cleaning is done easily thanks to the Dextens cleaning station sold separately look at the accessories paragraph 1 2 In most cases it is enough to start an automatic cleaning cycle to refresh the sensor and restore its initial performance for more information about this operation please refer to the cleaning station s user manual The following s are given here only for informational purpose 1 Connect the cleaning counter electrode to the sensor 2 Using a cable connect the sensor to the c
10. ens sensor has been designed to reduce the need of maintenance and to simplify this operation The service intervals can vary greatly from one measurement conditions The purpose of this chapter is to describe in depth the way to clean the sensor and the tools that are used for this 4 2 When to clean a sensor There is no definitive rule to when you clean a sensor nor is there a standard service interval Cleaning frequency is directly related to how much oxygen has passed onto the cathode However you should clean a sensor when is slow It is noisy e The calibration is out of range It is visibly dirty 4 2 1 Slow sensors When sensors are becoming slower they may need a maintenance The test procedure for detecting slow sensors is quite simple Plunge the sensor without grid and gauze in water saturated with sodium sulfite If the reading is below 10ppb after 10minutes the sensor is fast enough Unfortunately this test is not always possible for example for in line sensors In such cases the operator must detect sluggish responses by comparing the sensor speed over a chosen period of time 4 2 2 Noisy sensors First of all the sensor noise is only visible at low oxygen concentration 50ppb and below Above that limit the sensor noise is not significant The test procedure is similar to the speed detection Plunge the sensor in water saturated with sodium sulfite When the reading drops below 50ppb and a read
11. er with ammonia 30 e Puta few of drops on the cathode so it is covered e Wait 3 minutes Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch 19 Maintenance 3 Rinse the sensor abundantly with water for 30 seconds tap water is fine 4 Fill the cleaning adapter with nitric acid 65 Put a few drops on the cathode so it is covered Wait 10 seconds maximum 5 Rinse the sensor for 5 minutes with water tap water is fine Inspect the guard which should be uniformly white after the nitric acid cleaning If it is not repeat the cleaning exercise Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 20 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance 6 Fill the cleaning adapter with ammonia 30 e Puta few drops on the cathode so it is covered e Wait 3 minutes 7 Rinse the sensor abundantly with water for 1 minute 8 Put some polishing powder and distilled water on the polishing cloth 9 Place the electrolyte reservoir without membrane on the sensor Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 21 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance 10 Polish the sensor by making big circles until the silver ring between the cathode and the guard is shiny The sensor must be held vertically Do not p
12. event noisy readings due to sample turbulences in front of the sensor Sensor socket mounting side view SENSOR 28 mm CAO Mm 149 50 mm 79 50 mm 70 00 mm iie Lemo connector x Sensor collar Pipe adapter stopper for sensor 25 00 or sensor 28 PIPE ADAPTER FOR SENSOR 28 42 00 mm 34 00 mm I PIPE ADAPTER FOR SENSOR 28 mm Pipe adapter collar Be sure to remove the sensor socket s two O rings prior to pipe welding and re attach the sensor socket collar before welding begins This prevents distortion of metal threads during welding In line analysis puts the sensor in direct contact with the bulk sample flow This can be achieved in a number of ways The sensor can be positioned in a number of locations and sample conditions e Horizontally or with a small positive angle of 5 e On a horizontal stretch of pipe or on flow ascending vertical pipe e On the pump s discharge side and if possible at least 15 meters downstream e Sensor should not be installed on the suction side of a pump e Sensor should not be installed close to valves or bends in the pipe e Sensor should not be installed near air or carbon dioxide injection if no static mixer or frit is used The gas might not be dissolved and it might give lower reading than expected or gas bubbles exploding on the membrane surface will generate noisy readings 3 5 Insertion Extraction Valve Installation A pipe adapter would require the whole sys
13. he sensor 1 4 CE Conformity The TC sensors instruments are manufactured conforming to the requirements of the electromagnetic compatibility directive 89 336 CEE and the low voltage directive 73 23 CEE Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates m Switzerland 4 T 41 22 884 8306 F 41 22 342 48 60 info dextens ch www dextens ch 2 Indroduction 2 1 Content of Package oxygen sensor When ordering a 51100 oxygen sensor you will receive the following items 5110 oxygen sensor with its calibration cap 1 collar 2 and storage foot 3 This user manual 2 2 Accessories Depending on your order additional accessories can be delivered Part Nr 75502 mmm Cable for connecting the sensor to a process or portable instrument Part Nr 87410 87411 Sensor maintenancee kit Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 5 T 41 22 884 83 06 F 41223424860 info dextens ch www dextens ch Introduction Part Nr 73100 Cleaning unit Part Nr 74001 00 74002 00 Tuchenhagen insertion device for 225 or 28mm sensors Part Nr 74010 00 74011 00 Tuchenhagen adapter for 225 28mm sensors Part Nr 74003 00 74004 00 Pipe adaptor for welding for 825mm or 28mm sensors Part Nr 74006 000 74006 001 74007 000 74007 001 Stainless steel flow chamber for 225 or 228 sensors with 6mm or 7 fittings Part Nr 74009 000 PEEK flow chamber for 828m
14. ing in the handle the plunger should not touch the membrane yet The hole C is used for the filling syringe see slide 37 Remark 1 The electrolyte reservoir is opened when the dots are aligned Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 24 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance Remark 2 The reservoir is closed when the dots are not aligned 8 Connect the exhaust tube Place the open end in your electrolyte container 9 The syringe filled with electrolyte is connected to the hole C 10 The fully prepared filling station looks like this Before filling tighten the plunger so that it is touching the membrane with a light pressure Fill the reservoir by slowly squeezing the syringe closed until electrolyte comes out of the exhaust tube Shake the end of the sensor and make sure that there are no bubbles visible Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 25 T 41 22 884 83 06 F 41223424860 info dextens ch www dextens ch Maintenance 11 Now unscrew the plunger enough so that it is not touching the membrane to avoid damage to the membrane Close the reservoir by turning the body of the sensor from the open position shown here to the closed position the dots are not aligned 12 Unscrew the support fully and remove the sensor from the holder Shake the sensor and inspect the reservoir to make su
15. ing variation of 10ppb is noticed the sensor is noisy 4 2 3 Verification of Cleanness of a Sensor After cleaning the sensor the operator may want to check if it is clean before remounting it First of all make a visual control e The anode color must be a light grey look at pictures below e The cathode must be yellow color of gold without a white film e The guard must be grey silver color In case the cathode or the guard are do not have the correct color consider polishing the sensor If the anode is still dark repeat electrochemical cleaning as long as there are no bubbles present in the electrolyte Anode before cleaning Anode after cleaning Dextens SA 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 13 T 41 22 884 8306 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance 4 3 Maintenance tools and material The maintenance kit sold separately look at the accessories in paragraph 1 2 provides the necessary tools for cleaning the sensor and replacing the membrane Take a look at the picture below for a detailed description of the maintenance kit content Maintenance kit description Polishing Cloth Polishing Powder Electrolyte Bottle Sensor Holder Membrane Box Syringe Removal Tool Cleanin Adapter Exhaust Tube Wrench In addition to the maintenance kit you will sometimes need ammonia concentration 30 and nitric acid concentration 65 When handling these product always wear
16. leaning station Remark Orbisphere cleaning system can also be used with an adaptator Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 17 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance 3 Put the sensor on the sensor stand 4 Fill the counter electrode with electrolyte covering the cathode 5 Start the electro chemical cleaning on all electrodes 6 Select the component for cleaning either individually Anode Cathode Guard Or All three Press start stop button to begin cleaning the system will stop automatically when cleaning is complete the lights will no longer flash 7 Rinse the sensor abundantly with water tap water is fine particularly the space between guard and cathode Dextens SA 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 18 T 41 22 884 8306 F 41223424860 info dextens ch www dextens ch Maintenance Remark A suggested vessel to provide the stream of water looks like this 4 4 4 Aggressive Cleaning Most often you may skip the content of this section But when the sensor is very dirty for example after one year of continuous work or after membrane breakage it may be useful to clean the sensor with ammonia and acid In such case follow the few next s 1 Screw the sensor storage foot on to the base of the sensor and place the cleaning adapter in place of the electrolyte reservoir 2 Fill the cleaning adapt
17. m sensor with 6mm fittings Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 6 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Introduction Part Nr 71001 Storage foot Part Nr 71002 Calibration cap Part Nr 71003 Collar 2 3 Consumables and spare parts Depending on your order additional consumables and spare parts can be delivered Part Nr 82000 Box of 5 rubber gaskets Part Nr 82001 Box of 5 rubber gaskets with grill and gauze Part Nr 82952 Box of 5 Tefzel 25um membranes Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates m Switzerland 7 T 41 22 884 83 06 F 4122 342 48 60 info dextens ch www dextens ch Introduction Part Nr 82956 Box of 5 PFA 25um membranes Part Nr 82059 Electrolyte bottle 50ml Part Nr 82132 Polishing powder Part Nr 82134 Polishing cloth Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 8 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Installation 3 1 Introduction The oxygen sensor can be mounted in a sample by means of a flow chamber a sensor socket or an insertion extraction valve The following paragraphs describes how to uses these accessories The sensor interfaces the instrument via a 10 pin LEMO connector The standard sensor cable length is three meters but longer cable of up to 100 meters can be provided without any loss in signal sensitivit
18. ng 5 the membrane clean e Are there no bubbles in the reservoir Inspect the cathode guard and anode are they clean Even if they appear clean re clean the sensor we recommend both aggressive and basic cleaning and recalibrate and retest If after cleaning re cleaning and retesting the sensor is still not performing well we recommend you contact Dextens Dextens SA m 18 Chemin des Aulx m 1218 Plan les Ouates m Switzerland 29 T 41 22 884 8306 F 41 22 342 48 60 info dextens ch www dextens ch 8 Technical Specifications Membrane Utilization of various membranes according to measuring range Membrane model number 82956 82952 82935 Measuring range DO2 0 1ppb 20ppm 1ppb 100ppm 10ppb 400ppm Liquid flow rate 180 ml min 50 ml min 25 ml min Linear flow 200 cm sec 30 cm sec 20 cm sec Gaseous flow rate 0 005 3 l min 0 005 3 I min 0 005 3 I min Response time 90 7 2 sec 38 sec 2 5 min at 25 C Accuracy 1 of the measured value or lowest value whichever is greater Absolute zero and low drift Temperature compensation 5 C to 60 C 23 F to 140 F Temperature range CIP or SIP resistant up to 120 C 248 F Weight 0 6 kg Enclosure protection IP68 NEMA6P Material in contact Stainless steel ANSI 316L PFA or Tefzel with sample Sensor model number Model 51102 25mm Model 51101 28mm 3m standard length optional extension up to 1000 m Expected Oxygen Sensor Current Mem
19. re there are no bubbles visible If there are bubbles top up the reservoir to make sure that they disappear Inspect the cathode and guard with a magnifying glass to make sure that there are no air bubbles beneath the membrane 13 Replace the grid or seal as appropriate 14 Carefully replace the protective cap ensuring the grid seal remains properly centered 15 Replace the locking screw with the removal tool Dextens SA 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 26 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch 5 Calibration After cleaning the sensor it is mandatory to recalibrate the sensor on a Dexens 61100 instrument to ensure the calibration parameters are correctly written in the sensors memory Please report to the instrument manual for the detailed calibration parameters and procedure e Connect the sensor to an instrument e Start a calibration e Let the calibration stabilize 1 hour e After 1 hour efficiency should be in the range 80 to 120 If it is in this range confirm the calibration If not see trouble shooting at the end of this document For a good calibration be sure the sensor is completely mounted in its final setting and the Dacron gauze if installed is dry Not following these 2 rules is to get a bad calibration which will cause bad measurements The calibration is also a first way to check the sensor even if the instruments accept efficiencies from 5
20. ress the sensor on the polishing cloth Only use its own weight Avoid skin contact with the polishing cloth it should be kept free of dust and grease After use rinse the polishing cloth and dish with water and replace the lid to keep dust off the cloth 11 Remove the electrolyte reservoir and rinse the reservoir thoroughly 12 Remove the remaining polishing powder from the sensor and the electrolyte reservoir using water The best results are obtained when the water is targeted on the ring between the cathode and guard The cathode and guard should be shiny If they are not re polish as above Now inspect the cathode and guard with a magnifying glass ensure there are no polishing powder particles on the surface and particularly between the cathode and guard Note Following an aggressive cleaning we recommend a basic cleaning 13 Replace the electrolyte reservoir Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 22 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Maintenance 4 4 5 Reassemble the Sensor This is one of the most important part of the cleaning procedure If it is not done correctly the sensor s performances will be affected and in some cases it will be necessary clean the sensor again Therefore read very carefully this paragraph and understand the instructions 1 Select the right membrane e Black 82952 in line e Beige 82956 portable and pack
21. sed the reservoir But the effect of this problem can sometimes be detected after a quite long time because of a small leak The symptoms of this problem are a sensor that is not measuring anything and which becomes very sensitive to pressure changes To correct the problem do a complete maintenance taking much care to completely close the electrolyte reservoir 7 4 Dirty Sensor After some time in normal use the sensors becomes dirty They are much slower to go down and the response signal is quite noisy The only thing to do is a maintenance some times with a chemical clean see 84 4 4 7 5 Slow Sensor If when completing the sodium sulfite test the sensor does not reach 10 ppb in 10 minutes AND 0 4 ppb in 60 minutes then let the sensor sit for 1 hour connected to the instrument This will allow the sensor to consume any oxygen which may reside in the electrolyte e Inspect the sensor for air bubbles If there are none then retest the sensor speed If there are bubbles you must rework the reservoir to remove them either by topping up the reservoir or completely refilling it Note if you completely refill the reservoir you should recalibrate the sensor If the sensor is still not delivering to specification bullet point 1 above allow it to sit overnight connected to the instrument and retest If after testing and allowing the sensor to sit either for an hour or overnight performance is still not to specification check the followi
22. st screwing the insertion device collar the valve will open up placing the sensor in line Removal is accomplished by unscrewing the collar When unscrewing the collar the valve will close before the sensor can be removed avoiding any leakage of the sample This valve can withstand line pressures of up to 20 bar with or without the sensor in place The insertion device is designed so that the O rings sealing the valve will be also exposed to the CIP chemicals thus ensuring that hygiene is maintained 3 6 Kit 82400 for sensor in line Installation The in line measurement of oxygen requires the sensor to withstand harsh operating conditions in some applications When there is a sudden change in the line hydrostatic pressure the membrane can inflate resulting in erratic oxygen reading Dexens proposes a kit with parts to be inserted inside the hat shaped cap of the sensor This kit contains a tefzel washer a metallic grille a Dacron gauze and a silicone washer With such kit installed the sensor can withstand sudden and abrupt pressure variation of 7 bars Should you require to install such kit in your sensor you will need to dissemble the hat shaped cap as explained in section 3 3 and reassemble the sensor with the kit as explained in section 3 7 Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates Switzerland 12 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch 4 Maintenance 4 1 Introduction The Dex
23. tem to be shut down before the sensor could be removed for service For maximum flexibility without interfering with the production run or process a self sealing device such as Tuchenhagen housing together with a specially made hygienic Dextens insertion device allows the sensor to be removed by simply unscrewing the mounting collar which simultaneously closes the valve Dextens SA m 18 Chemin des Aulx m 1218 Plan les Ouates m Switzerland 11 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Installation The model 74000 74001 insertion devices are for sensor 51100 25mm and sensor 51101 28mm respectively It allows a sensor to be inserted or removed from a pipe while the sample is still flowing It clamps to the Tuchenhagen Varivent in line access unit which can be purchased directly from the manufacturer and is held into place by a stainless steel clamp Sensor installed in an insertion device cross section view INSERTION DEVICE FOR SENSOR 28 mm or SENSOR 25 mm Insertion Device Collar Location requirements are as stated above for the sensor socket To insert the sensor screw on the sensor collar until coming to a stop using the insertion device collar wrench provided The sensor is securely tightened using the wrench to screw up the insertion device collar The wrench is fitted with two small pins and one of them is inserted into the insertion device collar hole the two ones being located 180 apart Whil
24. un dissolved powder in the solution take care that it does not touch the membrane as this can damage the membrane Dextens SA m 18 Chemin des Aulx m 1218 Plan les Ouates m Switzerland 28 T 41 22 884 8306 F 41 22 342 48 60 info dextens ch www dextens ch Trouble shooting Even if Dexens sensors have been designed to reduce the sources of trouble some harsh working condition may lead to sensor malfunction This chapter is here to give some tips to find and correct the problem 71 Calibration outside of the defined range e Calibration below 80 it is possible that the reservoir is overfilled Open and close the reservoir to reduce pressure and re measure efficiency e Calibration above 120 membrane is probably too tight Place in warm water overnight and re measure efficiency 7 2 Punctured Membrane A common problem with our sensor is that the membrane is fragile and can be easily punctured or torn when not protected by the protective grill The symptoms of this problem are reading that are not going down or very slowly The only response to this is to thoroughly clean the sensor and replace the membrane When the membrane has been broken the sampling liquid enters the reservoir To get a fully working sensor you will remove all traces of the liquid 7 3 Empty Electrolyte Reservoir Another frequent problem is that the electrolyte leaks out of the reservoir This happens after bad maintenance when the operator has not completely clo
25. y 3 2 Sensor Dimensions Dexens provides 2 types of sensor diameters depending of the application requirements Look at the following sensor drawings to get detailed dimensions All accessories are made in 2 versions to be compatible with both sensor versions Sensor 51100 28mm 178 00 mm 149 50 mm SENSOR 28 mm 28 50 14 65 50 mm 70 00 mm Calibration cap M42 x 1 5 25 00 mm 28 00 mm Sensor collar S Sensor 51100 25mm 178 00 mm 149 50 mm SENSOR 0 25 65 50 70 00 Calibration 25 00 To x Lemo connector Sensor collar S Dextens SA m 18 Chemin des Aulx 1218 Plan les Ouates m Switzerland 9 T 41 22 884 83 06 F 41 22 342 48 60 info dextens ch www dextens ch Installation 3 3 Flow Chamber Installation The model 74006 or 74007 flow chambers are used to draw non carbonated or stilled liquid or gaseous samples past the sensor 61100 25mm and sensor 61101 28mm respectively They connects to 6 mm or 1 4 stainless steel tubing by means of two Swagelok fittings Stainless steel or plastic tubing with very low permeability is used as connecting tubing The sample enters the chamber via the center inlet port located on the flow chamber and the outer port is used as the sample out The flow chambers are designed to limit the sensor in contact with the sample to the membrane surface only When switching from a liquid sample to
Download Pdf Manuals
Related Search