OxyGuard ® PPB ppb Analyser for Dissolved Oxygen User`s Manual
Contents
1. manual Special training is NOT needed THE OXYGUARD PPB ANALYSER IS A SENSITIVE INSTRUMENT PLEASE FOLLOW THE INSTRUCTIONS IN THIS MANUAL CAREFULLY SPECIAL FEATURES FAST RESPONSE HIGH STABILITY NO REGULAR SERVICE NEEDS NOT SENSITIVE TO SAMPLE FLOW RATE EASY TO CALIBRATE FAST RETURN TO LOW PPB MEASUREMENT AFTER CALIBRATION FAST AND EASY MEMBRANE REPLACEMENT NO SPECIAL TRAINING NEEDED NOT CROSS SENSITIVE TO HYDROGEN If there are two ranges range selection is made by a HI LO range selector switch on the front panel Please read ALL this manual before using the instrument It is important to note that the probe functions best 1f you do NOT take it apart for maintenance 2 INSTALLATION NB IMPORTANT DO NOT REMOVE THE PROBE FROM THE TRANSPORT CHAMBER UNTIL IMMEDIATELY BEFORE INITIAL CALIBRATION THE PROBE IS BEST STORED IN LOW OXYGEN WATER THOROUGHLY FLUSH SAMPLE WATER PIPES BEFORE CONNECTION TO THE MEASUREMENT CHAMBER 2 1 General When planning installation please take any steps possible to ensure a stable accurate measurement Both the surroundings and sample should have a constant moderate temperature Do not subject the equipment to vibration or radiant heat Oxygen diffuses through plastics rubber etc Use metal pipes with welded brazed or metal joints for the sample water The flexible aluminium tubing supplied with the equipment is ideal Even though the system is not sensitive to elect2. 3 Measurement Chamber Installation The chamber has 6 mm pipe fittings and is supplied mounted on a plastic plate with two holes for easy fixing see the drawing at the end of the manual The inlet is normally to the left the outlet to the right but the chamber can be supplied with the opposite flow direction The sample piping must be thoroughly flushed clean before you connect it The measurement chamber is often fed with a sample flow that is led to a drain afterwards The check valve in the inlet means that you can turn the flow off or even disconnect the inlet for long periods and still retain low oxygen water from the last sample in the chamber so that the probe does not need to be removed during operation standstills The unit can also measure in a by pass loop at up to 6 bar pressure eg on stator cooling water In this case the insert must be removed from the check valve Make sure that the piping system generates sufficient pressure drop to ensure a flow of at least 100 ml min through the chamber 2 4 Sample Water Connections All sample water connections should be made in metal tubing such as the aluminium tubing supplied with connections either welded brazed or carefully made using metal compression ring fittings The sample should preferably be cooled to room temperature since this makes calibration even easier The sample temperature should be kept as constant as possible Flush all sample piping thoroughly and check th
3. on again f Check that the sample flow is approximately 100 ml min The 7 minute calibration timer blocks the alarm function sets the analogue output to 4 mA the 0 ppb value and changes the amplification of the system so that you always calibrate to 100 or corresponding corrected value A stable measurement should be attained after a few minutes depending on the oxygen concentration in the sample and the length of time it took to calibrate If calibration took a long time and you can see that the measurement value will cause alarm when the timer runs out you can press Cal Init twice to start another 7 minute period Calibration is now complete 3 2 Adjustment of sample water flow If necessary the sample water flow can be adjusted AFTER CALIBRATION If there is a limited supply of water the flow can be gradually reduced until the measured value begins to fall then When the sample line and increased to just over this value cooler if used are correctly established the If the reading falls when the flow is increased air is entering the measurement will be sample line Locate the leak and repair it constant over a very large flow range 3 3 Alarm Set Point Adjustment Push and hold the small black button under the Alarm Set control Adjust Alarm Set until the display shows desired value For single range models the display shows the alarm setting in ppb directly but in dual range models the meaning of di
4. single range but a dual range model is also available The OxyGuard ppb analyser consists of a transmitter unit and a probe with measurement chamber The transmitter has a display that shows the measured value a galvanically isolated analogue output and an alarm output It has a calibration timer which blocks the alarm output and sets the analogue output to its zero value so that calibration can be performed without triggering alarm The analyser can either measure a sample flow that is led to a drain or measure on a by pass loop at up to 6 bar pressure When used with the outlet to drain the measurement chamber is fitted with a check valve to retain water in it at all times The probe is shipped in a transport chamber that contains water with little or no oxygen and the probe should not be removed until all parts are installed and the probe is to be calibrated SPECIAL FEATURES It is important to note that the OxyGuard PPB analyser has a number of features that make its use and maintenance significantly different from that of other analysers for low level dissolved oxygen If you are familiar with other analysers you must be aware that the OxyGuard PPB analyser NEEDS MUCH LESS CARE AND ATTENTION THAN OTHER SUCH ANALYSERS If the probe should ever need attention i e if the membrane should suffer damage the necessary service can be performed by anyone on the basis of the spares shipped with the unit and the instructions in this
5. ON CLOSED SYSTEMS EG STATOR COOLING WATER REMOVE THE INSERT FROM THE CHECK VALVE BODY AND ENSURE THAT THERE IS ENOUGH PRESSURE DIFFERENCE TO MAINTAIN FLOW THROUGH THE MEASUREMENT CHAMBER amp we i 1 TO MAINS ANALOGUE SAMPLE sUPPLY OUTPUTS COOLER EH H gt ee FLOW DIRECTION ind NB USE METAL PIPE AND FITTINGS 1 2 1 2 3 DO NOT LET PIPING STRESS TIGHTEN WITH TWO SPANNERS THE MEASUREMENT CHAMBER 3 CALIBRATION AND ALARM SET POINT ADJUSTMENT 3 1 Calibration Calibration is an easy process that can usually be performed in less than two minutes It is advisable to make all preparations before removing the probe from the low oxygen content water It is important to note that the longer the probe is in air during calibration the longer it will take for it to return to its working point in very low oxygen content water The probe MUST have the same temperature as the air when it is calibrated If you adjust the sample water temperature to that of the air or place the probe in a beaker of low oxygen content water at air temperature some minutes before taking the probe up for calibration you will not have to wait a long time for temperature equalization For the greatest accuracy check the barometric pressure and find the calibration value from the table Otherwise calibrate to 100 Prepare to remove the probe from the chamber Clean its outside if necessary Note that the analogue output automatically goes to 4
6. OxyGuard PPB ppb Analyser for Dissolved Oxygen User s Manual Ser Nr Range Output Supply Div Delivery Checked by L01 PPB manual gb 0201 CONTENTS 1 DESCRIPTION 1 1 General 2 INSTALLATION 2 1 General sects settee sede be eS te tte 2 2 Transmitter 2 3 Measurement Chamber Installation 2 4 Sample Water Connections 4 3 CALIBRATION AND ALARM SET POINT ADJUSTMENT XL Galib Eation uses 3 2 Adjustment of Sample Water Flow sese 3 3 Alarm Set Point eee nennen 4 SERVICE AND MAINTENANCE 4T General tet ter eerte e a a tte ete a a t dete us 4 2 Fault Finding ere dr et nece taedet On ec Y eR Gee debida 4 3 Membrane 1 2 2 AA Sp r Parts jcc rnc ee da endl deu ean en hte 5 SPECIFICATIONS and DETAILED DESCRIPTION S L Transmitter 2e e e a Cet ob t a S 5 2 o R ESPE E tr Ete E OE AE Rae EEA DIMENSIONAL DRAWINGS 1 DESCRIPTION 1 1 General The OxyGuard ppb analyser is designed to measure dissolved oxygen in feed water condensate district heating water or similar The standard model has a
7. at it can deliver at least 100 ml min at a suitable steady temperature Connect the piping to the measurement chamber and prepare for calibration WHEN THE ABOVE HAS BEEN PERFORMED YOU SHOULD MAKE PREPARATIONS FOR CALIBRATION THEN REMOVE THE PROBE FROM THE TRANSPORT CHAMBER CALIBRATE IT AND PLACE IT IN THE MEASUREMENT CHAMBER AS DESCRIBED IN THE FOLLOWING NB Use two spanners to tighten fittings or you may shatter the measurement chamber NB The probe is not cross sensitive to hydrogen NB A flow of 100 ml min is sufficient The equipment will easily measure at larger flow rates but larger flow rates constitute a waste of water System configuration atmospheric pressure measurement AMPLIFIER DO NOT KINK THE LEAD LEAVE ENOUGH LEAD TO LIFT PROBE FOR CALIBRATION AND CLEANING ETC W xD 190 x 96 x 240 mm b 4 mounting holes centres 161 x 220 mm PROBE uL IL ALARM AND DO NOT LET PIPING STRESS SAMPLE TO MAINS ANALOGUE THE MEASUREMENT CHAMBER OUTPUTS COOLER SUPPLY hi TO DRAIN An n NB USE METAL PIPE AND FITTINGS 1 2 1 2 TIGHTEN WITH TWO SPANNERS System configuration measurement under pressure max 6 bar AMPLIFIER 1 DO NOT KINK THE LEAD LEAVE ENOUGH LEAD TO LIFT PROBE W xD xH 190 x 96 x 240 mm FOR CALIBRATION AND CLEANING ETC 4 mounting holes centres 161 220 mm 2 WHEN MEASURING UNDER PRESSURE
8. d or faulty cable or connections 4 2 3 An unstable display can also be caused by a damaged membrane check it and replace if necessary 4 2 4 If the probe seems to be sensitive to small changes in flow air oxygen is entering the piping or measurement chamber Inspect renovate the piping and chamber check all joints 4 3 Membrane Replacement THIS SHOULD ONLY BE PERFORMED IF THE MEMBRANE IS DAMAGED Switch off the unit Unplug and remove the probe Carefully unscrew the cap and discard the electrolyte The anode should be clean If there are deposits on the the drawings cathode it can be carefully cleaned in water or under the tap using grade 1000 emery paper The cathode must NOT be polished A new membrane must be fitted to the cap Unscrew the retaining ring in the bottom of the cap using the special tool provided Discard the membrane and the O ring The cap and retaining ring should be rinsed and dried thoroughly Place a new O ring in the bottom of the cap and a new membrane on top of the O ring Screw the retaining ring tightly into place The membrane must remain flat If it wrinkles remove it and try again with a new membrane and O ring It is important that all parts are completely clean and dry Rinse the probe in demineralised water Fill the cap to the brim with fresh electrolyte Hold the probe vertically move the cap up to the probe and gently screw it in place without turning it back at any time Surpl
9. ing temperature 5 C to 60 C Encapsulation IP 65 Input Voltage signal from the probe The input is galvanically isolated from the output Analogue Output 0 20 mA or 4 20 mA as ordered Max loop impedance 700 ohm For 2 range model 20 mA the full scale selected by range select switch E G 20 mA 100 ppb if LO selected and 1000 ppb if HI selected Standard Range 0 100 ppb 2 range version LO 100 ppb and 1000 ppb Alarm output 1 high alarm Potential free change over switch max 200 VA relay activates on rising or falling signal as ordered System Accuracy 1 ppb when measuring temperature calibration temperature Saturation Curve DIN 38404 part 22 1986 The transmitter consists of a cast metal enclosure with front panel assembly and a main circuit board The front panel assembly comprises the display an alarm set control calibration trimmer pushbuttons for alarm value display and calibration timer activation and indicator for calibration timer The main circuit board has terminals alarm relay power supply and input and output circuits The input is the microvolt signal from the probe The single range model has as standard a measurement range of 0 100 microgram per liter ppb the dual range 0 100 and 0 1000 microgram per litre selected using a small ALO HI witch The display can over range to 170 or 1700 but the analogue output is limited to 20 mA The analogue output in OxyGuard
10. mA the 0 ppb value when the calibration timer is running Barometric Pressure mmHg 730 740 750 760 770 mBar 973 986 1000 1013 1026 Calibration once every three months is often sufficient The probe will not suffer by being in the air for a day or two but it may take some time before it again measures accurately at a few PPB Temperature equalization has taken place when the reading is steady 780 790 1040 1053 Calibration 97 100 101 103 104 Value You can now proceed as follows a Press Cal Init to start the timer see that the yellow lamp is lit b Unscrew the ring and lift the probe from the chamber If it was in the transport chamber or measured a liquid other than clean water rinse it thoroughly in clean water Carefully dry the membrane with a cloth or soft paper Hang the probe in free air away from sources of direct heat Observe the display When the display reading is stable which usually takes about one minute adjust the CAL front panel trimmer until the display shows the calibration value d Place the probe into the chamber filled with water NOTE THE PLACING OF THE GASKET between the flange and chamber top e Ensure that the seal seats correctly and that air bubbles are not trapped in the chamber Tighten the ring If any bubbles are trapped turn the flow off for a few seconds the bubbles will rise to the top of the chamber and be flushed out when the flow is turned
11. pb in approximately 40 sec and to 10 ppb in less than 3 minutes The probe is a galvanic measuring element which generates a microvolt output proportional to the dissolved oxygen It is manufactured in stainless steel and consists of an upper part with cathode anode and cable and a cap with membrane and electrolyte The cable between the probe and the transmitter unit is a special screened 3 metre long cable with connector The cable and connector are EMC optimized to give the best possible noise protection The probe can be ordered with longer cable Oxygen diffuses through the membrane onto the cathode where it reacts chemically and then combines with the anode This chemical process develops an electrical current which is converted into a voltage of approximately 50 uV at 10 ppb via a linearization resistor The measurement chamber has 6 mm compression ring fittings and check valve in the inlet all mounted on a plastic plate ready for fixing with two 6 mm screws see the drawing at the end of this manual The check valve ensures that when measuring at atmospheric pressure water from the last sample remains in the chamber i e it remains filled with water even if the feed is turned off IMPORTANT When the measurement is made on a bypass under pressure e g on stator cooling water the check valve insert must be removed The probe is not cross sensitive to hydrogen N B The system has EMC CE approval Standard Accessorie
12. ppb analyser is galvanically isolated from the input and can be factory set to either 0 20 mA or 4 20 mA max load 700 ohms 4 20 mA is standard The alarm relay is usually coded to activate when the measured value rises above the alarm value The alarm set point value is shown on the display when the small black pushbutton under the Alarm Set control is held depressed The calibration timer which runs for 7 minutes is started and stopped by pressing the Cal Init button The yellow indicator lights when the timer is running during which time the alarm function is blocked the analogue output is set to the zero value and the amplification of the system is changed to enable calibration 10 In the dual range model the analogue output changes to correspond to the selected range Please note that the contact output is a potential free dry change over contact max load 200 VA at 230 VAC 5 2 Probe Probe dimensions 21 5 mm diameter x 135 mm with 3 m special cable Type Self polarizing galvanic membrane covered amperometric cell Sample temperature 5 C to SOEC Temperature compensation Automatic Measurement Chamber Clear acrylic chamber with 6 mm compression ring fittings and valve Sample flow Depends on oxygen content and temperature min 100 ml min max 2000 l min Sample pressure up to max 6 bar Response Time Less than 20 sec for 90 of a step change From 1 minute in air calibration to 100 p
13. rical noise it should as a matter of principle NOT be placed near sources of electrical noise 2 2 Transmitter Installation Mount the cabinet using the holes in the corners Connect as indicated below Do not coil up stretch or sharply bend the probe cable Place the probe cable so that the probe can easily be hung up for calibration Connect the probe still in the transport chamber and switch the transmitter on Please note that it can take 5 minutes for the equipment to warm up and stabilize 2 2 1 Electrical Connections LI III rp pov ov sem nc c wo nc ato geen sey Mains Supply Alarm relay Analogue Output NB The probe connections are effected via a factory wired connector The internal connections of the plug are as follows Probe connector transmitter socket and cable colours The pin numbers run clockwise starting at the index notch when looking at the socket on the transmitter unit from the outside THE FOLLOWING INSTALLATION PROCEDURE MUST BE CARRIED OUT IN THE STATED ORDER NB MAKE SURE THAT THERE IS ENOUGH ROOM TO THE SIDES OF THE CABINET TO RELEASE THE RIGHT SIDE LOCK WITH A LARGE SCREWDRIVER AND TO SWING THE TOP HALF OPEN To Probe NB It may in some cases be practical to shorten the cable The procedure is quite easy but the proper tools must be used To keep the EMC protection the probe cable must be without joins and terminated properly 2
14. s 2 m flexible sample tubing Membranes O rings Electrolyte User Manual Special tool The equipment is supplied ready for use Data subject to change without notice 11 Transmitter Unit k 190 Mounting hole centers 161 220 mm All dimensions in millimeter A 2 Measurement Chamber with Probe 2 holes 6 mm dia 90 approx 128 12
15. splay reading when setting the alarm limit depends on whether or LO is selected WHEN ALARM SET is held depressed If LO is selected a display of 200 means a set point of 20 0 ppb If HI is selected a display of 200 means a set point of 200 ppb Zero Check Zero check is not necessary but 1f you suspect that the zero has drifted a little please contact your supplier or OxyGuard International A S NB NEVER PLACE THE PROBE IN CONCENTRATED SODIUM SULPHITE SOLUTION 4 SERVICE AND MAINTENANCE 4 1 General There is no need for regular maintenance or service just keep the All necessary spares etc probe membrane free from deposits The membrane can be wiped are shipped with the unit clean with a cloth or soft paper Do not try to scratch it clean with a fingernail Remember to press Cal Init before removing it from the chamber THERE IS NO NEED TO CHANGE THE ELECTROLYTE REGULARLY The probe should not be taken apart unless the membrane is damaged e g due to accident when cleaning it 4 2 Fault Finding REMEMBER TO SWITCH OFF THE SUPPLY TO THE UNIT AND TO CIRCUITS CONNECTED TO THE ALARM OUTPUT BEFORE REMOVING THE FRONT PANEL OR TERMINAL COVER A HAZARD EXISTS IF THIS IS NOT DONE 4 2 1 If the system is completely dead first change the fuse 160 mA slow blow If this does not help consult your dealer 4 2 2 A sudden fault e g with a zero or negative display can be caused by a damage
16. us electrolyte should trickle from the screw thread It is important that the probe is completely filled and that the cap is screwed firmly in place The probe can now be regarded as new It can however take a few hours before it reaches its correct working point and stability It should therefore be calibrated mounted back in the measurement chamber and used for two days before being re calibrated 4 4 Spare Parts The OxyGuard ppb oxygen analyser system is manufactured from tried and tested parts of the highest quality so the need for spare parts is minimal The parts delivered with the unit should cover the need for spares for 20 years use otherwise spares can be obtained from OxyGuard PPB Membrane Replacement Probe Body lt yy 2 Discard electrolyte 1 Unscrew cap 7 Fit retaining ring 6 Place new membrane __ 5 Place new o ring 4 Wash and thoroughly dry 8 Fill with and retainer ring electrolyte 3 Discard used membrane and O ring lt C amp A Th 9 Assemble tighten cap gt firmly by hand 5 SPECIFICATIONS and DETAILED DESCRIPTION 5 1 Transmitter Construction Rilsan coated aluminium alloy enclosure with LCD display calibration and alarm set point adjustment terminals power supply electronics and alarm relay Dimensions bx dx h 190 x 240 x 100 mm Weight approx 3 kg Supply 230 VAC Other on request Operat
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