".

INSTflUCTION fIIANUAl

ORBECO-HELLIGEModels 965-10A and 965-10AR

Diiital, DL4ec~-~eadin~7Ufl8IDlfI1E.7EJlS

TA8lE. OF CONTlNTSSection

GENERAL DESCRIPTION and SPECIFICATIONS 1

QUICK OPERATING INSTRUCTIONS 2'

PROPER OPERATING and MEASURING TECHNIQUES 3

UNDERSTANDING TURBIDITY and its MEASUREMENT 4

CALIBRATION 5

RECORDER OPERATION and FLOW-THRU CELL 6MAINTENANCE, TROUBLESHOOTING and REPLACEMENT PARTS ..• 7

WARRANTY 8

onseco AIIAl!JTICAl S!JSTl/IJS, In.c..185 Marine st., Farmingdale, NY 11735Phones: 1-800-922-5242 631-293-4110

FAX: 631-293-8258

Section 1

The Kode1 965-10A Digita1 Direct-Reading Turbidimeter measuresthe clarity or cloudiness of any type of colorless fluid. It isideal for regulatory monitoring, process control and researchstudies. It can also be used in the field with optional No. 9994Voltage Converter and any 12vDC auto/boat battery. The 965-10Ameets the official specifications of the USEPA, ASTH, Standard~1ethods of APHA, AWWA, WEF and other world-recognizedauthorities. It meets the design requirements of USEPA Hethod180.1 and is ideal for NPDES and NPDWR compliance reporting.

A true nephe1ometer, the Hodel 965-10A tests at the officiallymandated 900 angle between its photo-detector and incidentlight beam. Its direct-reading LCD display gives results inNTUs (Nephelometric Turbidity Units) over three turbidityranges: 0-20.00, 0-200.0, and 0-1000. Test resolution is 0.01NTU in the lowest range.

The Kode1 965-10A is factory pre-ca1ibrated, and is ready forimmediate use. USEPA-approved primary calibration standards arealso included for convenient periodic calibration checks.

Its direct-reading ·digita1 disp1ay is drift-free. It providesautomatic error-free decimal shift and over-range indication.

Mode1 965-10A oEerates from yo~~_choice of 110 or 220 vo1ts,50/60 Hz. And an optional voltage converter permits portableoperation in the field, using any 12vDC auto/boat battery.

Kode1 965-10~ is identical to Hodel 965-10A, but in additionhas a recorder output for continuous turbidity monitoring ofpumped or gravity flow sample streams with optional No. 965-56Flow-through Cell, as described in Section 6.

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RANGES andRESOLUTIONin NTU

ACCURACY .REPEATABILITy ....

SENSITIVITy .

LIGHT SOURCE .

READOUT .

POWER REQUIRED ...

RECORDER OUTPUT ..(Nodel 965-10AR)

TEMPERATURE RANGE(Instrument only)

SAMPLE CELL .

TEST SANPLE VOLUME

STANDARDS SUPPLIED

INSTRUHENT SIZE ...

SHIPPING WEIGHT ...WARRANTy .

S'PffIFICA7IONS

LOW: 0.00 to 19.99 - resolution 0.01MEDIUM: 00.0 to 199.9 - resolution 0.1HIGH: 000 to 999 - resolution 1

62% of reading for low and medium ranges.~±,1%

,0.01 NTU, ±l digit.

10,000 hour Tungsten Lamp Bulb

3~ digit, ~" LCD with automatic decimal shiftand over-range indication.

User selectable for 100-135v or 210-240v,50/60 Hz, and also for 12vDC auto/boat batterywith optional No. 9994 Voltage Converter.

0-lv, 0-5 ma, adjustable for 10K ohm or higherimpedance.

Storage: -10oC to 700eOperating: oOe to 450C (Allow at least15 minute waiting period after change inambient temperature).

Optically matched glass vial with screwcap; 28mmOD x 61mm high; 6 supplied.20 mL minimum required.

Permanent USEPA-approved Primary, 40.0 NTU,non-hazardous; and Permanent Zero Standard.

28W x 24D x 13.5H em (11 x 9.3 x 5.3 inches).

5.9 Kg (13 lbs).

2 years; see Section 8 for details.

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Section 2QUICK Otpl.RATINiiINSTRUCTIONS

See Table of Contents and Sections 3 and 4for more detailed instructions and comments

Power: Use slide-switch at rear of housing to select 115 or230v, 50/60 Hz operation, and insert plug into grounded outlet.Push rocker arm POWER switch on. Allow at least 15 minutes forinstrument to warm up.

Remove red dust cover plQg from SA~'fPLECELL hole before testing.(Retain it to prevent dust penetration during inactive storage).Range selection: Set range knob for desired range: 0-20.00,0-200.0, or 0-1000 NTU. If the turbidity of the test sample ishigher than the range selected, the readout will show "1" at theleft side of the display. If this occurs, turn the range knobto the next higher range.

If sample contains large particles which cause readings to varywidely, switch to a higher range to lessen sensitivity.

Calibration: The ~10del 965-10A is pre-calibrated, and does notrequire standardization before use. (Do not unlock or rotatethe STANDARDIZE or ZERO knobs; refer to Section 5 for the simpleprocedure for checking the calibration periodically).

Qp"eration:1. Pour the test sample into a clean, dry No. 965-50 Sample

Cell, filling it to the neck. (For highest accuracy, makecertain the cell is not scratched). Cap cell tightly, andthoroughly wipe fingerprints from the outside with lintlesscloth or paper towel.

2. Holding the cell by its cap, gently swirl to mix (do notshake vigorously to catise bubbles) and push it downcompletely into the SA~1PLE CELL hole. Place the CellCover over the cap of the cell to block out extraneous light.

3. When the reading stabilizes, note the test result.

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section 3

IMPORTANT: For highest accuracy and reproduclb1e reBu1ha,give careful attention to these instructions and comments.

Use a "noise-free" power 1ine that is not shared by heavy-dutyelectrical equipment, elevators, etc. For safe and stableoperation, only use an outlet that is properly grounded.

For fie1d use with 12vDC auto/boat battery, set 115v operation,and connect power cord to optional No. 9994 Voltage Converter.Do not turn the Standardize or Zero contro1 knobs except whenchecking the calibration of the instrument -- see Section 5.

Use care in collecting samp1es. Make certain sample isrepresentative. Collect a "composite" sample when testing largevolumes. Rinse the container and its cap thoroughly withsample. Collect at least 20 mL. Close container, keep itprotected from temperature changes and excessive shaking.Avoid settling of turbid particles; test as quickly as possible.

Vital importance of cleanliness. It is imperative that thecontainers used to obtain samples, and the sample cells andstandards used with the instrument are absolutely clean, bothinside and out. This is vital -- we cannot stress it enough,especially when low values below 10 NTU are measured. Alwayswash and dry cells promptly after use. If stubborn residueshave adhered to the glass surfaces, soak cells with non-abrasivelab detergent, or use an ultrasonic cleaner. Flush thoroughlywith deionized water and air dry.Even the slightest fingermarks, stains or dirt can lead toinaccurate results. To avoid fingermarks, always hold cells bytheir cap threads or caps. If necessary, wipe the sides ofsample cells with an alcohol-treated lintless cloth or papertowel, and make certain they are dry before being inserted inthe instrument. Take care to avoid scratching cells in fixturesused for washing, drying, or storage.

Eliminate scratched cells and standards. Scratches or etchmarks may cause inaccurate results because they distort theinstrument's light path and falsely mimic turbidity. To checkfor scratches, turn the instrument on in a dark room and placethe empty sample cell (with cap removed) in the SAMPLE CELLhole. Slowly rotate the cell while looking down into thecell opening. Any scratches on the cell will be visible whenthe instrument's light strikes them as the cell is turned.

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If cells develop very small scratches, apply a thin film of No.R-409B Silicone Oil. Spread with lint free cloth and wipe offexcess. This has the same index of refraction as glass, and maytemporarily serve to eliminate the effect of such scratches.However, frequent use of this oil may foul the sample cell well.Cells with readily visible scratches should be discarded.

A1ways fi11 the samp1e ce11 to its neck. A lower meniscus maycause inaccurate results. Cap the cell tightly enough toprevent leakage and to avoid its coming loose when the cell islifted or held by its cap.

Avoid and e1iminate bubbles. Pour sample slowly and carefullyto avoid bubbles from forming and clinging to the inside cellwalls. If bubbles appear, swirl cell, strike bottom gently todislodge them or let cell stand with cover removed until bubblescan be knocked free by gentle tapping. Other degassing methodsinclude 1) warming sample 2) adding a surfactant 3) applyingpartial vacuum 4) ultrasonic bath. These methods must be usedwith caution to prevent changing the turbidity.

Avoid and e1iminate condensation. Condensation will causeinaccurate results and may damage the instrument. Generallycondensation forms when sample, cell with sample or standard,or the instrument itself is brought from a COlder location intoa moist and warmer one. All must be allowed to come to ambienttemperature. Condensation on cells must be carefully wiped awayuntil the cell sides remain dry. Simply wiping a condensation-clad cell once may be insufficient, as the condensation mayappear again if the sample is very cold, to cause readingerrors.

Never allow condensation or any liquids to enter the cell well.If this should happen, take immediate action -- see Section 7Maintenance.

Cell positioning or orientation. Holding the cell by itsscrewed-on cap, lower it all the way into the cell hole. Justthe top edge of the shoulder, and the cap, should be visible.The cells are specially selected to be uniform for all routinetests irrespective of how they are positioned, rotation-wise,in the cell well.

For extreme1y critica1 work, the use of one cell for calibrationand subsequent testing provides the best precision andrepeatability. A reference mark should be placed on the cell inthe following manner: Fill a cell with clear water and test inthe low range. Slowly rotate cell, over full 3600, noting thereadings as cell is turned. When the lowest reading isdisplayed, place a felt-tip reference line on the shoulder ofthe tube aligned with the "6 o'clock" location on the SAMPLECELL hole. Perform all subsequent tests with the same tube sopositioned. Protect the reference mark with nail polish so itwithstands repeated washing.

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If using only one cell is unacceptable, test a series of cellswi~h ~he same clear or turbid sample, and place a reference markon the shoulder of each at the position where they all give thesame reading.

A1w~~1ace the Ce11 Cover over the capped sample cell afterthe cell has been inserted into the cell well.

Ra~e se1ection and OVer-ranJLe. The instrument has threeturbidity ranges: Low, Medium, and High. These have the nominalreadings of 20.0, 200, and 1000 NTU (with a maximum digitaldisplay in each range of 19.99, 199.9, and 999 respectively).Unless the sample is known to have a very high turbidity, it ispractical to first test on the 0-19.99 range. If the turbidityis higher than this range, the readout will show the figure "1"at the left side of the display. Turn the range knob to the nexthigher range 0-199.9. Since the lower ends of the rangesoverlap, for greatest sensitivity and accuracy use the Low Rangeto cover 0-20, the ~1edium Range to cover 20-200, and the HighRange to cover 200-1000 NTU.

When testing a sam~1e with various sized~artic1es (such asunfiltered raw water) which may cause readings to drift or varyin the 0-19.99 range, switch to the 0-199.9 or 0-999 range.After filtration, return to lower range for higher sensitivity.

Samp1es over 400 NTU are best diluted 1:1 with clear tap water.See Section 4.6 for high range turbidity limitations.

Be aware of turbiditLchanges if sample is diluted or itstemperature changes. This is because the particles causing theturbidity may change in structure or size.Ambient Temperature Change. Allow at least 15 minutes for theunit to come to equilibrium after major changes in temperature.Cover the Ce11 ~~l to keep out dust when the unit is not in useand not in its carrying case. Insert a capped cell and coverwith the cell cap, or cover the unit with a plastic wrap.

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3-3

Section 4UNDeASTANDIN~ TURBIDIT!} an.d itA. AlASURlACNT

4.1 -- WHAT TURBIDITY IS

Essentially, turbidity is the optical effect that occurs whenlight strikes materials that are suspended in a fluid, and it isused to express the "cloudiness" of that fluid. The wordNephelometry, generally accepted as a specific method ofmeasuring turbidity, is derived from the Greek word for"clouds". It thus relates to the "measurement of cloudiness".

The substances that are suspended to form turbidity can varyfrom very tiny particles, to medium or large-sized ones. Theycan be "solid" particles like extremely fine silt formed fromriver or stream water grinding down rocks or stones. They canalso be "soft" gelatinous or organic debris or bits of decayingvegetable matter. In addition, some turbidity-causing particlesmay be suspended droplets of an immiscible fluid, such as oilemulsions. Even gasses coming out of solution as microscopicbubbles, which gradually float to the surface and cling to thewalls of the container, produce a turbid effect.

The particles can be any color -- white, grey, tan, green oreven jet-black coal dust. They can be opaque or transparent.The particles can be round, or have irregular or evencrystalline shapes. Others have no specific shape, such asfibers, irregularly twisted tiny hairs, lint-like structureseven agglutinated lumps or strung-together globs.

The density of the particles can vary also -- from "stone-heavy"solids which tend to settle to the bottom rapidly after stirringceases, to "equal-to-water" density chemical substances, fibers,or organic materials that will stay suspended in fluids for longperiods after stirring has stopped.

Certain substances dissolved in water, such as sulfates andchloride, can be reacted with reagents to produce turbiditiesdirectly proportional to their concentration. The instrument isideal for such turbidimetric analysis.

Turbid cloudiness can be present in many colorless fluids otherthan water, such as biochemical solutions and pharmaceuticalproducts where suspensions or emulsions are present. with propertechnique, these can be measured with the instrument.

4.2 -- HOWTHE INSTRUMENT MEASURES TURBIBITY

Simply stated, turbidity is measured by directing a beam oflight into the side of a cell containing the test sample,

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measuring the amount of light that is reflected at a 900 angleby any particles present, and comparing it to the lightscattered by a Bbandard reference suspension. The light beam isprovided by a special lamp powered by a regulated internal powersupply. The intensity of the light reflected at 900 ismeasured by a stable photodetector, amplified, and displayed ona digital readout.

The amount of light is directly proportional to the degree ofturbidity. At zero turbidity, no light is reflected ormeasured. The more particles that are present, the more lightis reflected to the photodetector, and the higher the reading.Special design and construction prevents stray light frominterfering with the measurement.

The term FTU (Formazin Turbidity Units) is used to express theresults of a turbidimeter which has been calibrated withFormazin, as explained in Section 5. The Model 965-l0Aqualifies for this, and also for the expression of its resultsin terms of NTU as explained below.

The term NTU (Nephe1ometric Turbidity Units) is used to describethe test result of a measurement performed with a modern 900

turbidimeter (like Orbeco-Hellige Turbidimeters), rather thanless exacting turbidimeters (like the Jackson Candle, orineffective "straight-through-the-sample" photoelectriccolorimeters). Since the Model 965-10A is based on a Formazinstandardization, and in addition fully qualifies as a true 900turbidimeter, you may express results in FTU or NTU, whicheveris most common in your work, as you wish. The USEPA considersthe terms interchangeable.

UNDl~STANDIN~TU~8IDITJAlAJU~GMlNT

4.3 -- TURBIDITY IS NOT ALWAYS STABLEIt is important to understand that the measurement of turbidityis a changing, dynamic phenomenon. The masses of particles thatcause turbidity are not always uniform -- sometimes they arelike ever changing fog, heavy mists or rapidly changing cloudsin a thunderhead -- turning, spiraling, drifting lower orhigher, denser one moment and less dense another. Because ofthese often changing conditions, completely stable readingsshoUld not always be expected.

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4.4 -- COMPLEXITIES OF ACCURATE TURBIDITY TESTINGEven though the 965-10A is a most advanced, state-of-the-artturbidimeter, there can be samples where testing must be donewith a good understanding of the phenomenon involved. Sometimesvariable size of particles, presence of lint, fibers, "strings"of particles, etc., must be dealt with. Consider the followingpossibilities.

A. Effect of large particles in the sampleAt times particles or foreign matter in a solution are solarge or irregular in shape that turbidimeters cannotaverage them properly. This causes the digital display todrift and change readout values. Switching to the nexthigher range may dampen the readout changes, so that anaverage value of the digital readings may be estimated.To check if erratic results are being caused by largeparticles, unscrew the cap from the sample cell and, whilethe uncapped cell is in the instrument (best in a darkenedroom to avoid extraneous light), turn the instrument on andlook directly down into the sample with a strong magnifier.Large contaminants may be visible in the illuminated field.Note: Readings without the screw cap may not be valid.

To try to alleviate this problem, pre-filter any sample thatappears to be contaminated with large particles and debris.Use a coarse screen or net, no less than 100 microns, andpour the sample through it. This should rid the sample oflarge particles which can cause measurement errors, withoutadversely affecting readings of the main, less-than-largeparticle sample.

B. If particle sizes in the sample vary greatlyIf all the particles remain suspended, the reading willrepresent an average of their optical properties.

If some particles tend to settle out rapidly while othersremain suspended, the readings will Change at a rateproportional to the settling rate. Therefore, if a plot ismade of several readings and their time intervals, aninterpolation can be made of the true initial value beforesettling started. Recorder Model 965-l0AR can be veryuseful in making such measurements. (Non-recorder Model965-10A can be converted to recorder use; contact CustomerService) .

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C. If partic1es in the samp1e are uniform in size, but aregross1y different from the partic1e size of the standardIn such cases, the optical refractive index may also bedifferent from that of the standardizing solution. Try touse a standard as close to the apparent value of the unknownas possible. Most likely the readings obtained ininstruments of different manufacture will be significantlydifferent. Such comparisons should therefore not be made,except to use the results as relative values.

4.5 -- USE SPECIAL CARE WHEN MEASURING BELOW 1.0 NTUspecial cleaning and drying precautions should be taken. Useonly scrupulously clean cells, and dry them using a cleanfiltered air supply, or dry tank nitrogen. Holding the cell bythe threaded end, carefully inspect all surfaces under brightlight to assure that no scratches, stains or foreign materialsare present. Carefully wipe the cell after filling, beforeinserting in the instrument.

4.6 -- HIGH RANGE TURBIDITY LIMITATIONSsamples with very high turbidity may exhibit a condition called"going blind" in which the measured turbidity is lower than theactual turbidity because a significant amount of scattered lightis blocked by particles and does not reach the detector.

The U.S. Environmental Protection Agency recommends that fordrinking water turbidity testing, higher ranges should only beused as indicators of required dilution volumes to reducereadings to less than 40 NTU. The USEPA apparently feels thatturbidimeters can most accurately be calibrated at values of 40NTU or less, and waters which give higher readings should becarefully diluted with water of zero-turbidity, and the resultsmultiplied by the dilution factor. Our optional No. 966-ZT ZeroTurbidity Outfit contains everything necessary to produce zero-turbidity water for diluting purposes, with completeinstructions; see listing of accessories and replacement partsin Section 7.4.

Even if you are not required to follow USEPA procedures, it iswise not to use direct readings over 400 NTU. Instead, diluteand multiply the result by the dilution factor.

4.7 -- EFFECT OF COLOR. Sample color is due to dissolvedsubstances that absorb light. Colored samples may causemeasured turbidity to be low.

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4.8 -- NON-AQUEOUS SOLUTIONSThe Model 965-10A can be used for measuring the turbidity ofnon-aqueous solutions. However, due to the differences ofrefractive index, the instrument may have to be recalibratedwith a suitable standard. Contact Customer Service for details.

4.9 -- SUSPENDED SOLIDS cannot be directly related to turbidityvalues. Although turbidity readings vary with increasedsuspended solids measurements, there is no generally acceptedconversion factor. This is because of possible differences inrefractive index, and differences in size, composition anddensity of the particles present.

4.10 -- WHY DIFFERENT BRANDS OF TURBIDIMETERS GIVE DIFFERENTRESULTS

Turbidimeters of different manufacture, even when calibratedwith the same standard, may give different results on the sametest sample, because of several factors. Some pass the lightthrough the bottom of the cell while others pass it through thesides. Some have imperfect ways to try to eliminate stray light.Some use photodetectors that change with temperature changes.Another uses a photomultiplier which ages with time, and thushas varying response. Merely meeting the USEPA specificationsis by itself no positive guarantee, as they are not technicallyspecific to details, and subject to interpretation.

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4-5

Section 5

CAlI8'iM7ION

The 965-10A Tur_b:L(H_I!.Et.t:..~ __ :Ls_, supp1ied a1rea<!Y.."Ere-ca1ibrated. Thecalibration confirmation is very quick and simple. It can beperformed whenever desired.

For U.S. Environmental Protection Agency (USEPA) reporting underthe National Pollutant Discharge Elimination System (NPDES) orthe National Primary Drinking Water Regulation (NPDWR) permits,calibration check of all turbidimeters is required at leastevery 4 months. For this purpose a Zero and 40.0 NTU PrimaryStandard is supplied. Here's how to use them.

5.1 -- Checki~ZERO and 40.0 NTUca1ibrations.

Set range switch to the 0-200.0 range (the calibration of theother two ranges will be automatically performed by theinstrument's electronics).

Wipe the outside of the Zero standard clean. Holding it by itscap, lower it into the Sample Cell hole and cover with CellCover.

If reading is not 00.0, adjust with the ZERO calibrate lock-control. This consists of two parts -- an outer ring that mustbe pushed down to unlock the control, and a central knob whichcan then be rotated clockwise (to increase the reading) or 'counter-clockwise (to decrease it). Releasing pressure on theouter ring locks the setting of the central control knob.

Press the outer ring down with the thumb and forefinger of onehand. Then, with the other hand move the central knob a smallamount, note reading, and continue to turn in small increments,until 00.0 is reached. (If the display shows negative numbers,this signifies that the Zero control is set too far counter-clockwise; it is "below zero". Rotate it clockwise through thenegative numbers until 00.0 is reached).After the Zero calibration has been confirmed or adjusted,proceed with the 40.0 NTU primary Standard. Use a scrupulouslyclean, unscratched dry sample cell. It is good practice to pourapproximately 5 mL of the standard into the cell, swirl it torinse, and pour it out. Repeat this step twice, however, toprevent contamination, nELver..,Eourused _st.CL1l..dar_dl:;>a~kinto thePrimary Standard bottle.

Fill the rinsed cell to the neck with 40.0 NTU Primary Standard,and cap the cell. Repeat the calibration operation with the40.0 NTU stand rd and the STANDARDIZE lock-control until areading of 40.0 NTU is reached.

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5.2 -- Ca1ibration Standards.The 40.0 NTU standard supplied is a primary standard made withstyrene divinylbenzene spheres in an aqueous solution, and meetsUSEPA regulations. It ia highly accurabe, s~able andreproducible. It is more convenient and economical to use thanFormazin and is completely non-toxic. It is recognized by theUSEPA, ASTM, APHA et al as a primary standard -- its value doesnot have to be checked against Formazin. It is NIST traceable.

The 40.0 NTU standard has a guaranteed shelf life of one year.Replacements are listed in Section 7.

IMPORTANT: Protect the standards from freezing. If distincttiny crystals have formed and the liquid does not appear as auniform haze, replace it.

5.3 -- Sea1ed Secondary Standard.The cell which you have just filled with primary standard, andcapped tightly, may be used for future calibration checking, asa secondary standard. When you have completed the primarycalibration outlined in paragraph 5.1 above, make a permanentfelt-tip mark on the shoulder of the cell at the point where italigns with the "6 o'clock" location of the sample cell hole.This capped (sealed) cell can now be used as a secondarycalibration standard for routine, periodic use. Wheneverdesired; insert cell, rotate it to align the mark on itsshoulder with the 6 o'cloc]( position of the cell hole, and checkthe calibration. Note that the USEPA requires that allturbidimeters used for its regulations should be calibrated atleast every 4 months with a primary calibration standard.

5.4 -- Formazin Ca1ibration.Those who wish to calibrate the 965-10A with Formazin may do so,but are cautioned that although 4000 NTU Formazin is reported tobe stable for 1 year, dilutions of Formazin are far less stableand cannot be stored (even under refrigeration) for longperiods. This requires repeated, costly, and inconvenientpreparations of standards. Further, Formazin standards changevalue at different temperatures.For those interested in calibrating with Formazin standards, weoffer a convenient kit (No. 966-FO) which contains five stableconcentrates and equipment to make zero turbidity water. Eachconcentrate can be diluted with zero-turbidity water to make200 mL of 200 NTU Formazin standard for direct use, or fordilution to any desired lower values. Complete directions areinCluded. Note: Diluted Formazin standards are not stable, andshould be prepared fresh daily.

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5.5 - CALIBRATIONS FOR TURBIDIMETRIC CHEMICAL TESTS and PRODUCTGRADING

Scientific literature details chemical procedures which developa turbidity in proportion to the amount of substance under test.For example, procedures are available for sulfate and chloridein water, and for several biochemical tests. For sulfatetesting, we offer No. 965-65 Sulfate Outfit, which containseverything needed.

The 965-10A can also be calibrated for a variety of productgrading applications, such as for suspensions, colloidalsolutions, turbid fluids, etc. Call our technical staff forhelp. Give range desired, sensitivity needed, type of sample tobe tested, sample temperature, whether turbid standards of theproduct are available, specific procedure preferred, if any,and other pertinent information. We'll be glad to assist you.

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Section 6

RlCORDl1l 0'l'l1lA710l

The output of Turbidimeter Model 965-10AR equipped for recorderhas been factory set to be used with an external meter accessoryof 1.0 ma at approximately 1 volt. If a recorder requiring alower voltage input is to be used call for technicalassistance.

US£. OF COl116UOUS FlO"-TII1l0U~H ClllThe optional No. 965-56 Flow-through Cell, for use with RecorderModel 965-10AR permits continuous monitoring and recording ofthe turbidity of a constantly flowing stream or sample.It is ideal for many applications, especially in research ortesting the effect of turbidity-treatment methods or chemicalssuch as flocculents, precipitants, etc., or the effects ofbuffering, temperature adjustment, or physical settling andfiltering systems. In addition, it can be used for continuousliquid product quality testing, or grading surveillance of theclarity of edible oils, emulsions, oil-in-water mixtures,hydraulic fluids, and in many other special applications,where clarity or turbidity standards can be established and usedto calibrate the instrument.

The flow-through cell has the advantage that calibration andsubsequent calibration checking is extremely simple. Theflow-through cell, with its inlet and outlet tubes stillconnected and functioning, need merely be momentarily removedfrom the sample cell well (without interruption or need to shutdown the system), while a calibration standard is substituted inthe sample cell well. The calibration can quickly be confirmedor adjusted, and the flow-through cell can then be replaced inthe sample cell well after the calibration standard is removed.

Its design helps to keep the cell "self-cleaned". The incomingfluid tube in the cap is specially positioned to forcefullydirect the sample in a powerful jet directly against the insidewall of the cell. The curved inside wall of the cell directsthe flow in a strong circular whirlpool fashion, swirling thesample to forcefully cleanse the inside of the cell, until thefluid exits via the hose connection at the center of the cap.

-~"

WARNING: The flow through cell has not been designed for usewith strong acids and various organics which can attaCk itsplastic parts. Check with our Technical Service or runcompatibility tests before proceeding.

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Installation and use. Check the calibration of the instrumentas described in Section 5. Remove the standard and simplysubstitute the flow-through cell, with its input and outputtubing attached. Be careful to connect tubing securely, andtwist its cap on tightly to avoid leakage into sample cell well.

Connect the input tubing to the source of fluid, and outputtubing to drain or receiving tank, etc., and allow flow tostart. Flow can be by pump or gravity, but should be controlledby valving, pinch clamp or other means. WARNING: Do not exceed5 psi (pounds per sguare inch). Regulate pressure if necessary.Use eye protection and handle with care. We recommend aprotective barrier around the glass cell.

Check that air has been purged from flow-through cell by liftingit from the sample cell well for inspection. Tilt or rotate ituntil all air has been swept through, then lower it back all theway down into the sample cell well.

Be careful that temperature changes do not cause bubbles orcondensation to appear on cell vall. Cold sample streams shouldbe pre-warmed to eliminate condensation before sample entersinstrument. Bubble-traps or degassing should be employed toprevent bubbles from entering or forming on the cell. Forsamples with heavy debris or grossly mixed particle sizes,pre-treat by skimming, settling, centrifuging, floatation,coarse filtering, etc., to obtain desired results.

If vater or condensation seeps into sample cell veIl,immediately remove cell and disconnect electrical plug frompower receptacle. Remove the 6 screws at the front and back ofthe top instrument panel, and lift it off to be able tothoroughly dry out the insides. Use forced warm (not hot) airstream to aid drying, if necessary.

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6-2

Section 7AAI NTE.NANCl -- 7ROU8llSHOOT I N~

ACClSSORIlS an.d Rlf>lAC[J1JEJl7 f>A'A.75

The instrument has been designed and constructed to give yearsof trouble-free service. Do not allow dust, debris or fluids toenter the sample cell well. Cover the well or the entireinstrument when not in use.

?"....l. LAMP BULB REPLACEMENTThe No. 966-54L Lamp Bulb in the instrument has an average lifeof 10,000 hours. Should it fail or have a reduced output (asnoted when standardize control can no longer bring the readingto the correct value), it should be replaced as follows:Disconnect electrical power. Remove 6 screws that hOld the toppanel to bottom housing. Carefully lift back Of top panel untilupright, held by the wires connected to the circuit board in thebottom housing. The lamp bulb assembly consists of a lamp bulbembedded in a small metallic cylinder, with 2 wires ending inpolarized "quick-disconnect" connectors. It is held in place bya Phillips-head screw at one end of the optical bench mounted onthe top panel, near the instrument's on/off switch. To replacethe lamp bulb assembly, pull apart the 2 connectors (pliers maybe necessary), loosen the Phillips-head screw, and withdraw themetallic cylinder. Insert a new lamp assembly into the holeuntil ~ inch of the cylinder still protrudes, then gentlytighten the Phillips-head screw to hold the cylinder in place(don't overtighten; too much force may damage the bulb). Attachlamp's 2 connectors to corresponding ones in bottom housing.Reinstall top panel with its 6 screws. Check the calibration(Section 5) to ensure accurate results.

7.2 INSTRUMENT NOT WORKING?If unit is not operating at all, or incorrectly, confirm voltagesetting and review the following points. (If it functionscorrectly but results appear wrong, see Section 7.3 below).1. Check that indicator light of power switch is on.

2. Has sample cell been filled all the way to the neck? Itmust have 20 mL of fluid in it. Is it free of obstructionsuch as a label? Walls of cell must be unobstructed.

3. If lamp does not light (as seen looking down test well) whenpower light is on, see 7.1 above. If lamp lights but displayis blank, return instrument (see Note A below).

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4. If display digits remain at or near zero, make sure you areon the right range. Look down test well to see if bulb isout or very dim. Open instrument and check if lamp wiresare tightly connected. With caution (best by technicallytrained person) confirm that lamp voltage is 2.5v. If lessadjust trimpot next to lamp wires. If voltage is correctand lamp does not go on, replace. If lamp is OK but displaydoes not change, check for obstruction in well. If stillunsatisfactory, return instrument (see Note A below).

5. Standard reads low. Standard may have deteriorated.Replace or if Formazin standardization is preferred,prepare fresh Formazin standard and avoid settling errors bygently swirling cell to mix before inserting and reading.

6. Display fluctuates between 2 adjacent values. Nothing iswrong. Note values and report average.

7. Cannot adjust standardize control to display desired value.Lamp may be failing; replace even though it still lights.

8. Figure "1" appears at left of display. Rotate rangeselector to next higher range. If zero standard results infigure "1" at left of display, turn zero control counter-clockwise until zero is displayed. If this can't be done,return the instrument for service.

NOTE A -- If it is difficult to return instrument for repair,and if you have access to a competent electronic repair person,contact factory with problem details, for instructions.

7.3 WHEN TEST RESULTS ARE IN ..2..UESTION

If the instrument itself seems to be functioning correctly, butthe test results seem to be wrong, first thoroughly reviewSections 3, 4 and 5, and then the fOllowing:

a. Has the sample been taken correctly? Has it changed invalue due to settling over time, exposure to heat or cold,or to being kept in a container that contaminated it?

b. Were sample cells clean and dry before use? Free of fingermarks and scratches? Are sample cells scratched or stained?Bubbles clinging to insides of cell? Condensation outside?

c. Have cells been filled to the neck, positioned all the waydown into cell well? Is cell cover being correctly usedover the capped sample cell to keep out ambient light? Isinstrument shielded from strong light?

d. Have standarizing knobs been accidentally misadjusted? Hascalibration been correctly performed? Are supplied

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calibration standard or Formazin standards still valid?(Dilute Formazin standards are usable only for a day orless!).

e. What are results being compared to, that appears to signifyquestionable results? Are those readings necessarily valid?

When communicating with us regarding results, please givevery complete details of all aspects of your observations,standards used, their age, types and description of samplesbeing measured, and successful results as well as problemsencountered.

7.4 -- OPTIONAL ACCESSORIES and REPLACEMENT PARTS.9994965-50

965-55

966-51

R-4092.~

R-4095R-4094

965-59

965-60

965-56

R-4098966-54L965-16

966-FO

R-3401P

966-ZT

965- 65

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Voltage Converter, for use with 12vDC auto/boat batterySample Cells, Optically Selected, pkg of 6

Cell Cover

Package of Zero and 40.0 NTU Primary Standards

Zero Standard4.0 NTU Primary Standard40.0 NTU Primary Standard

Carrying Case, Watertight

Carrying Case, Utility Grade

Flow-through Cell, for Model 965-10AR

Silicone Oil

Lamp BulbInstruction Manual for Models 965-10A and 965-10AR

Formazin Calibration Outfit Complete (R-3401P + 966-ZT)Formazin PermaPak

Zero Turbidity Outfit

Sulfate Calibration Outfit

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Section 8lIA17lD 'AttAN7J

Orbeco Analytical Systems, Inc. warrants Models 965-10A and965-10AR Turbidimeters to be free from defects in material andworkmanship for a period of two years from date of shipment.Warranty for expendable parts (such as glass sample tubes,calibration standards, lamp bulbs) is limited to 30 days fromdate of shipment.

To put the warranty into effect, fill out and mail the enclosedProduct Registration Form to us within 2 weeks of your receiptof the instrument. This will enable us to record you as ownerand send you news on new accessories and other information.

This limited warranty shall not apply to any instrumentsubjected to misuse, negligence, accident, shipping damage, orstorage under adverse conditions ...to any instrument modifiedor used other than in accordance with the instructionsfurnished ...to any instrument repaired or altered by personsnot authorized by us, in a manner to affect (in our judgement)its performance, safety, or reliability.Contact us for instructions before returning any instrument.We may upon inspection of the returned instrument, at ourdiscretion repair or replace it, or make an appropriate creditadjustment or prorated refund, for any instrument or accessorythat fails to meet our specifications.

This warranty is in lieu of any other, expressed or implied,including those of merchantability or fitness of purpose. Wereserve the right to make chang~s in design or manufacture ofour products at any time, without notice, without incurring anyobligation to make changes in other units.

We shall in no way be liable for damage, consequential orincidental, due to defects in any of our products, for thefailure of delivery, for injuries to persons or property,or for any other cause.

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OR8ELOANAlJ7ICAl 5!J5TlJI'J5, In.c..185 Marine st., Farmingdale, NY 11735

Phones: 1-800-922-5242 631-293-4110FAX: 631-293-8258

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