DOM-1 - Dissolved Ozone Monitor Brochure

ECO SENSORS, INC.D I S S O L V E D O Z O N E M O N I T O RModel DOM-1(Patent Applied For)INSTRUCTIONS FOR USE GENERALThe DOM-1 is designed for monitoring dissolved ozone in the 0-2 ppm range, and to send controlsignals to external devices. A key principle of the DOM-1's operation is removing the ozone fromthe water so that it is read by the sensor in air. This is accomplished by a proprietary strippingchamber. Removing the ozone from water before measuring it eliminates or substantially reducesinterference from other chemicals such as chlorine and salt. It also avoids fowling of the sensorby various water borne contaminants. The DOM-1 has a digital readout in ppm of dissolvedozone, a set-point controlled relay closure to external devices such as an ozone generator, and a4-20 mA signal output to a computer or PLC. The instrument is designed to be operated atnormal room temperature only. The calibration will change at other temperatures, but it is easilyadjusted if the user has an independent method of measuring the dissolved ozone concentration.The DOM-1 has two subsystems: a Stripper Assembly and an electronics unit. The stripperassembly takes a small continuous sample (<.2 L/min or about 3 gallons/hour) from the waterline, strips ozone from it, and sends the ozone-in-air continuous sample to the sensor in theelectronics unit. The stripper assembly also filters the incoming water for general particulates andsolids; it has a pressure regulator to bring the sample stream to a standard for the stripperchamber of 10 psi (.7 bar); it has a tap and spigot just before the stripper chamber to take asample of the water for testing by another instrument; and it has a pressure gauge to indicate ifthe mechanism in the stripper chamber is clogging up. There is no wiring to the stripperassembly. It does not contain any electronics. The stripper assembly must be mounted so thatthe stripping chamber is in a vertical position (the water input and air tubing at the top; the drain atthe bottom).The electronics unit includes the HMOS ozone sensor, electronic circuitry to provide the digitalreadout, 4-20 mA signal output, and relay set-point. The electronics unit also houses the air pumpfor the stripping chamber (which makes an audible vibratory noise because it is a diaphragmpump); the pump's intake cartidge air filter which should be replaced annually, the catalytic ozonedestruct filter for the incoming sample from the stripping chamber, and any special electronics orpower supplies. The input to the electronics unit is 12 VDC, 800 mA, unregulated. The connections between the stripper assembly and the electronics unit are two lengths of plastictubing with 3/16" (5 mm) ID. These tubing lengths must not be changed because this factor isincluded in the calibration. INSTALLATIONThere are four major installation steps for the DOM-1 that should be planned in advance of theequipment delivery. They are (Refer to figures 1 and 2):21 - Connection from your process to the DOM-1 stripper assembly. This should be as short aspractical to avoid significant ozone decay loss in its slow passage (.2 L/min or 3 gallons/hour)from your process pipe to our stripping chamber. It should be preferably ozone-resistant plastictubing to damp out any vibrations from your equipment to ours and to make inter-unit alignmenteasier. There should also be a valve between your pipe and our stripper unit so that the waterflow can be cut off when installing or working on our equipment. A single turn chemical resistantvalve is recommended. The water input to our stripper assembly can be to a 1/4" NPT femaleinput in the strainer unit, or to a 1/4" (6-7 mm) barb hose adapter. Be sure that the sample valvejust below the gauge is closed (handle perpendicular to the flow channel).The stripper assembly could be mounted by standoff clamps from a wall. It should be oriented sothat the water flows in horizontally and the drain output of the stripping chamber is pointing down.It is important that the stripping chamber be maintained in a vertical position (the air tubing andwater inlet at the top). See figure 1.2 - Water recovery from our stripper assembly to your plant. The drain from our stripping chamberis a coil of 3/8" ID (9.5 mm) plastic tubing which ends about 8" (200 mm) below the strippingchamber. It is fitted to the tubing barb at the bottom of the stripping chamber. This .2 L/min drainflow can be conducted to your wastewater system or in some applications and systemsrecirculated back into the plant water flow. The loop in the tubing is to act as a "P trap" to pull allthe water out of the stripping chamber but to avoid free airflow through the drain passage.3 - Connections between the Stripper Assembly and the Electronics Unit. There are two 2 foot(600 mm) lengths of 3/16" ID (5 mm) chemical-resistant tubing that interconnect the two unitsusing the pair of tubing barbs found on the bottom right of the electronics unit and at the top of thestripper assembly. Either tubing can be attached to either barb. There is no inherent directionalitythat need be maintained. Before attaching to the barbs on the stripping chamber the two tubingsare run through the black hold-down clip on the side of the chamber to organize and secure thetubing.Do not connect the tubing from the stripping assembly to the electronics unit until the strippingassembly has been tested with water under pressure. The tubing should not be connected to theelectronics unit until you are certain that no water is leaking through the tubing. The water couldseverely damage the sensor and other components in the electronics unit. The Electronics Unit has three mounting points: a keyhole at the upper center in the back, andtwo lower corner side holds accessed by removing the access cover at the lower edge of theElectronics Unit.4 - Power to the DOM-1 The DOM-1 requires an AC adapter that delivers 12 VDC unregulated at800 mA. Most common adapters of this nominal rating deliver 12-14 volts which is an acceptablerange for the DOM-1. The adapter can plug into the center+ power jack on the bottom of theDOM-1 or can be wired to the terminal block in the left side of the access tray in the DOM-1.Alternately, 12 VDC can be brought in by standard electrical conduit from elsewhere in your plant.The conduit can attach at a knockout at the bottom of the electronics unit and the 12 VDC wiringmade to the terminal block just inside. Be sure that good earth grounding practice is followed.AC ADAPTERThe AC adapter for the DOM-1 should have a nominal 12 VDC unregulated output at 800 mA.Many 12 VDC adapters are available at 500 mA, but this is exactly the DOM-1's consumption.Therefore a 500 mA adapter is likely to run fairly warm (or hot) and so a higher current ratingadapter such as 800 mA is strongly recommended. The input power jack accepts plugs with thecenter + and plugs that mate to either a 2.1 or 2.5 mm center pin in the jack.3OUTPUT CONNECTIONSThe external connections to the outputs of the DOM-1 are made to the terminal block locatedinside the access cover on the lower part of the DOM-1 enclosure. The terminal block is wired asfollows:12 VDC (800 mA) Terminals for power input as an alternate to the power jack on the bottom ofthe unit (see figure 2).GND Independent connection to your earth ground. Is connected to the two - terminals.4-20 mA Current output proportional to the dissolved ozone concentration. Scaled as 4 mA = 0ppm and 20 mA = 2 ppm.Relay The relay contacts are rated 5 amps 250 volts and its set-point is the control on the left sideof the front panel. NO-C are the Normally open contacts when the concentration is below set-point; and NC-C are the normally closed contacts when the concentration is below set-point.Eco Sensors, Inc. can also supply data conversion modules to convert the DOM-1 4-20 mAoutput to RS-232, RS-485 multiple relay set-points, etc. Most of these modules are made by RedLion.STARTUP AND OPERATIONDo not connect the tubing from the stripping assembly to the electronics unit until the strippingassembly has been tested with water under pressure. The tubing should not be connected to theelectronics unit until you are certain that no water is leaking through the tubing. The water couldseverely damage the sensor and other components in the electronics unit.There is no on-off switch to power up the instrument. Simply plug in the AC adapter or connect toother DC power. Digits will appear on the panel meter, and you will be able to hear the air pumprunning. Leave the instrument running all the time, if possible, to keep the sensor warmed-upand purged of unwanted contaminants. We recommend running the electronics unit for 8-24hours before attempting to use the instrument. With no water from your process yet entering the DOM-1 stripping chamber, the digital readout ofthe DOM-1 should read 0.00. If it reads slightly higher, there may be some work area ozoneworking its way into the sensor. This effect should disappear when water is running through thestripping chamber.Now open the valve from your process pipe to the DOM-1 stripper assembly. Check for leaks inthe stripper assembly and tighten any connections as required. Be sure to maintain the strippingchamber in a vertical position (water inlet on the top). 12 VDC GND 4-20 mA Relay-- + - + N.O. C N.C.4If you have ozone dissolved in your process water, the DOM-1 should start to read within 10-30minutes. Startup requires a longer time until an initial ozone readout because the ozonated waterhas to flow through the stripping chamber for a few minutes, and additional time is required tocarry the ozone to the electronics unit and to sensitize the sensor which has been inactive.Once the electronics unit is reading ozone, it will adjust to changes in the dissolved ozoneconcentration within tens of seconds.The Pressure Gauge and Standard PressureThe gauge should read 10 psi and in a short while water should start trickling into the draintubing. As long as you are within +- 10% of 10 psi you are OK. The purpose of the gauge is toindicate when something is going wrong (such as downstream blockage) by the gauge readingabove or below its usual pressure.If the gauge is reading much higher than 10 psi, and there is no water in the drain tubing, there isa blockage in the stripping chamber. Contact Eco Sensors, Inc. for a solution.If the gauge reads near zero and a lot of water is in the drain tubing, the internal system in thestripping chamber needs repair. Contact Eco Sensors, Inc.If the pressure reads almost but not exactly 10 psi, you can do one of two procedures:1 - Adjust the pressure regulator (loosen the annular lock nut on the top and slowly screwdriveradjust for 10 psi) or2 - Mark on the gauge face your present pressure. Deviations greater than about 10% from this "standard pressure" indicate that something is wrongdownstream in the water channel or up stream in the pressure regulator. Pressure regulatorproblems can arise due to corrosion or blockage of its components.Check that the stripping chamber is trickling water (~ .2 L/min) to the drain. Avoid blockages ofthe stripping chamber drain. Observe the semi-transparent air tubing to be sure that water hasnot filled the stripping chamber and is flowing through the air tubing to the electronics unit. If thisis the case, immediately shut off the water to the stripping assembly and disconnect the air tubingconnected at the bottom of the electronics unit to prevent water from penetrating the electronicsassemblies.Adjusting the calibration You may want to adjust the DOM-1's calibration to agree with yourpresent in house standard such as a sample-based colorimeter. We recommend running theDOM-1 for 1-3 days first before attempting this to make sure all systems are understood andstabilized. Also this should be done when the ozone concentration is not changing in the waterand at a concentration typical for your operation. Referring now to figure 1, take a test samplefrom the sample valve to measure by other instrumentation the dissolved ozone concentration. Atthe same time record the reading of the DOM-1. IMPORTANT: At this time, record the setting of the multiturn adjustment control at thelower right of the DOM-1 front panel. This is the factory calibration, and you may want toreturn to it or discuss it with Eco Sensors, Inc. The reading will be 1 digit from the littlewindow and two digits from the control periphery.Recalibration to agree with your existing standard is done simply by simple ratio adjustment. Forexample if the DOM-1 reads .90 ppm with a calibration potentiometer setting of 565 when yourexisting standard reads 1.00 ppm, reset the calibration potentiometer to 565 X 1.00/.90 = 628.5The DOM-1 calibration is sensitive to temperature, and any other instrument will be sensitive totemperature or interfering gases or chemicals, so the agreement between the DOM-1 andanother instrument should be checked from time to time to refine the basis for agreementbetween the two instruments.Adjusting the relay set-point The DOM-1 relay has a set-point which can be adjusted over the0-1ppm range. The LED just above it goes on when the dissolved ozone concentration is belowset-point. This could be used for example to indicate that the ozone generating system has failed.The relay has both normally open (N.O.) and normally closed (N.O.) contacts which can beconnected to remote external readout or alarm devices. The relay contacts are accessed at theterminal block under the access cover. Full scale (full clockwise) on the relay set-point control atthe lower left of the DOM-1 control panel is 10. The best way to set it to an exactly desired ppmset-point is to wait until that ppm appears on the digital readout, and slowly rotate the set-pointcontrol until the LED just changes from on to off or off to on.4-20 mA output This is a standard current loop output set at 0 ppm = 4 mA and 2 ppm = 20 mA.Its output would typically go to a PLC (programmable logic controller). The 4-20 mA contacts areconveniently available at the terminal block under the access cover.MAINTENANCEComponents of the DOM-1 that should be regularly checked and serviced are:Strainer Remove by unscrewing transparent bowl and rinse strainer and bowl in running water. Pressure Regulator Could eventually fail due to constant ozone attack of plastic parts. Stripping Chamber Could foul or clog as evidenced by significantly increased back pressure and no exit water flow or no back pressure and excessively large water flow. Air Filter in Electronics Unit Check by removing tube from output air connector on bottom of electronics unit. Should be about 3 liters/minute flow. Filter accessed by removing access panel at bottom front of electronics unit. Do not attempt to clean. Replace. Over 3-5 years, the sensor, catalyst ozone destruct pack, or air pump may need replacing.Should this be the case, it is probably best to return the instrument to Eco Sensors, Inc. forcomplete maintenance. At that time, the sensor should be replaced and recalibrated.CALIBRATIONThe DOM-1 is shipped from the factory tested with ozonated water and calibrated against a Hachmodel 850 digital colorimeter. Accuracy is better than 20% and 10% is typical. We recommendchecking the DOM-1 calibration against a standard such as dilution chemistries or indigo dyecolorimeter tests at least every 3 months.Recalibration to agree with your existing standard is done simply by simple ratio adjustment. Forexample if the DOM-1 reads .90 ppm with a calibration potentiometer setting of 565 when yourexisting standard reads 1.00 ppm, reset the calibration potentiometer to 565 X 1.00/.90 = 628.The DOM-1 calibration is sensitive to temperature, and any other instrument will be sensitive totemperature or interfering gases or chemicals, so the agreement between the DOM-1 andanother instrument should be checked from time to time to refine the basis for agreementbetween the two instruments.6SPECIFICATIONS.Outputs: Relay contacts (normally closed and normally open), and 4-20 mA.Response time and warm-up: Response time up to 10's of seconds. More than one hour warmupand running recommended.Temperature range: 20-30 degrees C unless recalibrated for a specific temperature.Supply voltage required: 12-14 VDC 800 mA. Relay ratings: SPDT non-latching. Contacts: 5 amps at 250 volts AC.Protection Classifications: IP 52. Enclosure is polycarbonate. Front cover is clear polycarbonate. Size and weight: Stripper assembly: Approximately 305 X 305 X 153 mm (12" X 12" X 6") .4 kg (.9 lbs) Electronics unit: 318 mm wide X 267 mm high X 127 mm deep (12.5" X 10.5" X 5") 2.0 kg (4.4 lbs.)PRECAUTIONS• Read all instructions in this manual.• Review safety procedures in testing and operating this system.• Call a qualified electrician if you have any doubts about voltages, wiring, electrical codes andpractices, etc.• Keep the electronics and sensor dry. • Do not drop the electronics unit. Damage may not be immediately obvious.• Operate this system in areas of normal room temperature. Operation at extremetemperatures will require recalibration for operation at those temperatures.When in doubt, operate the system at least 24 hours in your worst case environment as a test.LIMITED WARRANTYThis product is warranted against defects in materials and workmanship for own year followingthe date of purchase by the OEM. This warranty does not include damage to the product as aresult of misuse, damage, modifications or alterations, and it does not apply if the instructions inthis manual are not followed. If a defect develops during the warranty period, Eco Sensors at its election will repair the productor replace it with new or reconditioned product of equivalent quality. In the event of replacementwith a new or reconditioned product, the replacement will continue the warranty of the originalmodel. To return this system or any module of it, call your distributor or OEM. OEMs and distributors callEco Sensors at (800) 472-6626 or e-mail at: sales@ecosensors.com to receive returninstructions and a Return Goods Authorization (RGA) number.Except as provided herein, Eco Sensors makes no warranties, express or implied, includingwarranties of merchantibility and fitness for a particular purpose. Eco Sensors shall not be liablefor loss of use of this instrument or other incidental or consequential damages, expenses oreconomic loss, or claims for such damage or economic loss.KEEP THIS MANUAL AND WARRANTY FOR YOUR RECORDS.Eco Sensors is a registered trademark of Eco Sensors, Inc. © Eco Sensors, Inc. 2003 Rev. 5/037Figure 1 - Stripping AssemblyShowing Wall Mounting AttachmentsTop View Pressure gauge to indicate Flow problemSample tap for externalcalibration instrumentPressure regulatorset to 10 psi (.7 bar)Inflow from your water lineStrainershould be cleanedregularlyStripping chamberTubing to electronics unitAir in from pumpAir with ozone out to sensorptMount P Trap asshown ClamTightening nutfor support bolSpacer nutWasherButterfly nut formasonry orsheet rock8Figure 2 - Electronics UnitDigital readoutDissolved ozone, ppmSetpoint LEDRelay setpoint adjustAccess area(cover removed)Calibration adjustAccess to lowerMounting holesMounting hRear View Showing Mounting HolesDC power jack Terminal block Air filter Air/ozone in Air out(replace as (tubing to strippingnecessary) assembly)oles