Solartron

Transducers

Density transducers

for hydrocarbon and process

applications

Liquid Density

Continuous high

accuracy measurement

Custody transfer

approved

316L Hastelloy andNi-span С versions

Insertion and by-pass

models available

Entrained gas option

Advanced Density System

Direct analog and digital outputs

Modular design

Local display

Comprehensive calculations

Diagnostics

Intrinsically safe

EMC approved

High accuracy, repeatabilityand stability are the hallmarksof Solartron's field provenliquid density transducers,These densitometers are the

Industry Standard for high accuracyapplications.

The Advanced Density System is a state of the art on-board electronics package designed to interface withthe Solartron 7835/45/46/47 range of tubedensitometers.

Gas Density and Gas Specific Gravity

High accuracy and

resolution

Continuous

measurement

Fast response

Intrinsically safe

Long term stability

Custody transfer

approval

Solartron's gas density and gas spe-cific gravity transducers are designed

to meet the requirements of gasmetering stations for custody

transfer, fiscal metering, qualityanalysis and energy management.

Liquid Density Measurement

The Solartron field proven range ofdensitometers have been designed tomeet the most demanding applica-tions found in modern processingplants. These meters have long beenrecognised as the Industry Standard.

Where the high accuracy of the 7835series is not required the 7826 InsertionDensitometer provides the idealsolution. This unit can be mountedeither in a static tank or in a pipeline.

All Solartron densitometers areavailable with a choice of flange andmaterial of construction. This allowsthem to be used in a broad range ofprocess liquids ensuring that Solartronhas the answer to your metering andcontrol requirements.

Fiscal MeteringThe 7835 is designed for fiscal meteringof crude and refined hydrocarbons andnon corrosive process liquids. Thistransducer offers the highest accuracywith excellent repeatability underpipeline operating conditions. Thevibrating element is manufactured fromNi-Span-C for excellent long term andtemperature stability.

General ProcessSuitable for most general processapplications, the 7845 is manufacturedwith all wetted parts in AISI 316Lstainless steel. Typical applicationsare:

• Percentage mass, percentagevolume and specific gravity of fluidsor fluid/fluid fluid/solid mixes.

• Caustic soda blending, Concentratedproduct delivered by road tanker isdiluted with water for on-sitestorage.

• Energy conservation in whiskydistilling. Used to monitor thealcohol content and shut off heatsource when the value of thealcohol falls near the cost of theenergy consumed.

• In the sugar industry for controllingdegrees Brix.

• Interface detection

• Blending control

Corrosive ApplicationsFor corrosive applications where AISI316L stainless steel is not suitable, the7846 offers wetted parts in HastelloyC22.

Hygienic ApplicationsSolartron densitometers are widelyused in the food industry for themonitoring and control of foodstuffs, forexample, milk and yogurt. The 3A-authorised, all stainless steel 7847 withspecial bellows make it an idealsolution. Various sanitary fittings areavailable for the transducer.

Insertion DensitometerThe 7826 Insertion Densitometer hasbeen developed for applicationsrequiring liquid density measurement inpipelines or static tanks.

The 7826 consists of a tuning forkarrangement with the tines mountedfrom a flange, which in turn supportsthe electronics housing. Thetransducer is available in a range offlange options, including а ЗАauthorised unit. An integral 4-20mAversion is available.

Principles of OperationAll Solartron liquid density transducersoperate on the same general principleand can be likened to that of a springmass system. As the product densitychanges it in turn changes the vibratingmass, which is then detected by achange in the resonant frequency.

When a mass on a spring is displacedand released it will oscillate at a naturalfrequency until it comes to rest due toviscous damping. An oscillation at thenatural frequency may-be maintainedby supplying a driving force toovercome the effects of damping.

Advanced Density Sys

The resonant frequencycan be derived as: 1 r^

Where: К is the stiffness. M is the mass ofthe element (M,) plus the mass of the fluid (Щ.If К and M are all constant then:

Hence >p = Ко + Ют2

The equation is further enhanced by theaddition of a K- term to improve linearityand therefore the final equation becomes:

p = Ko +К-Г+К2Т 2

CalibrationSolartron transducers undergo rigorousfactory calibration on three fluids: air,Century oil and a high density fluid (nonCFG). Initially the units are pressure testedto 1.5 times the operatingpressure. With Centuryoil in the calibrationloop the rig isfirst raised in ...,:,,

temperatureto determine the

temperature coefficientof the transducer and

'.' •-' then increased in pressure/'' to determine the pressure

coefficient.

To ensure that the production unitsare accurately calibrated to a high

megrity the calibration rigs have two

transfer standards built in. The densityreadings from these transfer standardsmust agree within certain limits, thusensuring that the rig has stabilised. Oncestabilisation is achieved readings ofperiodic time from each of the productionunits can be taken on Century oil and thehigh density fluid. From these results andwith results from an air calibration, the finalcalibration of the transducer iscalculated. -я̂ .̂

The transfer standardtransducers are calib-rated in an in houseBritish CalibrationServiceapproved

iNAMAS)laboratory

in three fluids.The density of

each calibration liquidd e t e r m i n e d by

Displacement methods to•A'\ uncertainty of 50ppm, A

number of meters from each batchare overchecked in this laboratory to

3rify the accuracy of the calibration.

7835 7845Error sourcesPrimary standard 0.05Kg/nfTransfer standard . 0.1Kg/m3

Instrument accuracy 0.15Kg/m3

(at calibration conditions)Temperature +/-0.005Kg/m3/°C +/-0.05coefficientPressure effect +/-0.006Kg/m3/bar +/-0.006

0.1Kg/m3

0.35Kg/m3

The factory calibration datum is 20°C and1 bar absolute. When operating at otherconditions it is necessary to increase theuncertainty of measurement, The overallaccuracy is the RMS error of the aboveerror sources. For example at 40°C and 30bar, 7835 accuracy = +/-0.25 Kg/m ,7845 = +/-1.07Kg/rrf.

The Advanced Density System (ADS) is a state ofthe art electronics package designed to interfacewith the Solartron 7835/45/46/47 range of tubedensitometers. Located in the head of thetransducer the ADS has been designed as amodular system which allows additional functionalityto be added as required. The transducer can beinterfaced DIRECTLY to a DCS, PID controller orother plant processing equipment via the digitalcommunications link or via the 4-20mA outputs. In

the majority of cases there is no need for additionalelectronics, since most standard calculations are

„ performed within the unit thus providing a veryI cost effective solution.

The transducer leaves the factory with all calibrationfactors and initial configuration stored in EPROM onthe meter. This means that from initial power up thetransducer provides an accurate output of linedensity and temperature, without the need forextensive programming. The only additionalconfiguration which may be required is theoptimisation of the outputs to suit the particularapplication.

rstem

Measurements and Calculated Data

All Solartron liquid density transducers measure twoprime parameters, line density and temperature.From these two prime measurements the ADS canperform a number of calculations, for example: -

Referred density (matrix & API)°API%Mass% Volume°Brix°BaumeSpecific gravity.

Outputs

The baseboard provides four separate outputs

• Two 4 to 20mA outputs, which can beconfigured to output any measured or calculateddata.

• One pulse output which provides either tuberesonant frequency or an alarm status.

• One RS485 digital communications link normallyfor use with the remote display.

The RS232 / RS485 and the HART board provideadditional digitai communications capabilities. Ifdesired the HART board can be used purely as athird 4-20mA output.

Baseboard

The baseboard is the heart of the system, utilisinghigh performance low power microcontroller to:-

• Perform the complex calculations previouslyperformed in a separate flow computer or signalconverter.

• Store all the transducer's calibration data,significantly reducing the level of customerprogramming ,

• Ensure that the transducer is operating correctly,providing several diagnostic facilities for theservice engineer,

• Facilitate digital communications with the remotedisplay or other computer systems (e.g. PC,PLCorDCS),

• Provide two direct analog outputs.

The baseboard aiong with the liquid density transducer provides a complete system formeasuring liquid density and temperature. However, if outputs need to be configured inthe field or if additional functionality is required then a remote display or option board maybe used.

Remote Display / Keypad

This unit is intended for either hand held or wall mounted use. It provides a convenientmeans for displaying calculated data and for configuring or analysing the system setup.The display can be operated up to 100 metres away from the transducer andcommunicates with the baseboard via an RS485 digital communications link. Thedisplay is of an intrinsically safe design and can therefore be mounted in the hazardousarea.

Option Boards

Three option boards are available for fitting to the baseboard:

• Switch board - providing a low cost means of configuring the system, and offerssome flexibility on system functionality.

• HART board - providing full HART communications and an additional 4 to 20mAoutput and full system functionality,

• RS232 / RS485 board - providing additional serial communication capabilities andfull system functionality.

Gas Density and SG Measurement

Solartron gas density meters havebeen serving the hydrocarbon industryin custody transfer of natural gas forover two decades. The 7812 gasdensitometer is the latest in the rangeand replaces both the 7810 and 7811meters.

7812 DensitometerThe Solartron 7812 gas densitytransducer is designed to meet therequirements of custody transfermetering stations by combining highperformance with safety. The sensor isdesigned for insertion mounting intothe gas flow path, either directly or in athermowell pocket, but with the gassample brought to the instrument via asample loop. This instrument satisfiesthe requirements of on-line densitymeasurement as in ISO 5167 andAGA3.

The pressure retaining parts of the7812 gas density transducer aremanufactured from NACE compatiblematerials. The transducer is approvedby CENELEC for use in all categories ofhazardous area.

Principle of OperationThe transducer sensing elementconsists of a thin-walled metal cylinder,resonating at its natural frequency. Thegas flows over both surfaces of thecylinder and the mass of gas in contactwith the cylinder depends upon thegas density. Since increasing the massdecreases the natural frequency ofvibration, the gas density can be'determined by measuring the resonantfrequency,

3096 Specific Gravity TransducerThe Solartron 3096 Gas SpecificGravity transducer provides a direct

on-line measurement of gas specificgravity or normal density for custodytransfer, standard volume flowdetermination, quality analysis andenergy management. The 3096 is mostfrequently applied in deriving standardvolume and energy flow measurementsof natural gas, where the exceptionalaccuracy and repeatability are of directbenefit.

3096 Principle of OperationThe 3096 consists of a vibratingelement gas density transducersurrounded by a constant volumereference chamber retaining a fixedquantity of gas known as the referencegas.

The reference gas pressure actsthrough a separator diaphragm on thepressure control valve chamber so thatthe gas pressure on both sides of thediaphragm is equal. Temperatureequalisation is achieved by temperaturestabiliser coils and a thermal insulationcover,

The Basic TheoryThe specific gravity (G) of a gas is theratio of its molecular weight (M) to thatof standard air. However, under settemperature (T)and pressure (P)conditions, with thesuper-compressibilityfactors (Z) taken intoconsideration, specificg r a v i t y a n d r e l a t i v edensity are synon-ymous. The density ofthe sample gas (p)by definition is:

and since a fixed quantity of referencegas is contained in a constant volume,then:

P, PT-J- = y5^ = К (a constant)

Under equalized pressure andtemperature

= KM, with identical Z factors

Thus the output signal from the densitytransducer is a measurement of themolecular weight or specific gravity ofthe sample gas.

P' =PM-

Z,RT

Liquid Density 7826 7835 7845 7846 7847

Wetted parts material

Density accuracyDensity repeatability

v/ Density rangev Calibrated density range

Operating pressure (max)

Pressure coefficient

Temperature range

Density temperature coeff

Safety approvalPower supply

Liquid Density

SS316LHastelloy C220.001 g/cc0,0001 g/cc0-3 g/cc -0.6-1.25 g/cc

207 bar(3000 psi)negligible

50°Cto+160°C(-58°Fto320°F)±0.0001 g/cc/°C

EExdlCT4.CSA24-2ЛЩ 50mA

NiSpan С

0.00015* g/cc0.00002 g/cc0-3 g/cc0.3-1.1 g/cc

150 bar(2175 psi)

SS316L

0.00035* g/cc0.0001 g/cc0-3 g/cc0.6-1.6 g/cc

Hastelloy C22 SS316L

0.00035* g/cc0,0001 g/cc0-3 g/cc0.6-1.6 g/cc

50 bar(725 psi)

0.00035* g/cc0.0001 g/cc0-3 g/cc0.6-1.6 g/cc

20 bar(290 psi)

±0.000006 g/cc/bar

50°C to +110°C (-58°F to + 230°F)-50°C to +160°C (-58°F to + 320°F) with high temperature kft

±0.000005 д/ссЛС ±0,00005 д/ссЛС

EExial!CT6, CSA

*0.0001 available with additional calibration.

Advanced Density System

Transducer performance

Analog outputsNumberAccuracyRepeatabilityOut of range capability

Pulse output

Communication options

Configuration options

Calculations

Safety approval

EMC approved

As above,

2 (+ 1 with HART option board)± 0,1 % of reading plus 0.05% of full scale.±0.025%2-22mA on 4-20mA (programmable alarm state)

Open collector output, alarm status or frequency

HART, RS232, RS422, RS485, Modbus.

Remote display/keyboard, switchboard, via communications protocol.

Line density, line temperature, Base density, "API, °Brix, °Baume, % solids,% mass, % volume, specific gravity.

EEx ia IIC T4. Class 1, Division 1, Groups B,C,D

Emissions: BS EN 50081 -2: 1994 Heavy industrial environment.Immunity: BS EN 50082-2: 1995 Heavy industrial environment.

Gas Density/Specific Gravity

7812 3096

Density accuracy

Density repeatabilityDensity rangeSpecific gravity rangeOperating pressure (Max)Temperature rangeProcess connection

±0.1% reading (Nitrogen)± 0.15% reading (Natural Gas)±0.01% reading0-0.4 g/ccN/A250 bar (2625 psi)-20°C to + 85°C (-4°F to + 185°F)1/4" NPT (API) female

± 0.02%N/AunlimitedRegulator used to set input pressure-30°C to + 50°C (-22°F to + 122°F)1 /4" compression fitting (6mm) pipe

Signal Converters

The 7945, 7945V, 7946 and 7946V SignalConverters are designed as easy-to-useunits which will process signals from aSolartron density or viscosity transducerwith additional live inputs of temperatureand pressure. Computation within theconverter includes transducer correctionand calculation of line or referred densityand viscosity.

These Signal Converters are capable ofperforming numerous calculations inaddition to the basic density or viscositycalculation. Each converter can alsoperform one of the following additionalfunctions:-

Liquid applications: -

• Degrees API

• Degrees Baume

• Degrees Brix

• Calculation of percentage Mass orPercentage Volume of a liquid-liquid orliquid-solid mixture or slurry.

Gas applications:-

• Calculation of Calorific value in terms ofvolume or mass from gas SpecificGravity using AGA 5.

• Calculation of Wobbe Index from gasSpecific Gravity and Calorific value.

• Conversion of line density to basedensity using line and referencepressure and temperature.

The Signal Converters inputs and outputsare detailed below: -

• 1 channel density / viscosity input.

• 3 analog inputs.

• 1 temperature RTD input.

• 4 status inputs.

• 2 analog outputs.

• 5 relay outputs.

• 1 Bi-directional RS 232C or RS485/422 communication port.

Full details of all these productsare contained in the brochureslisted below

Product

7835 Densitometerspecification

7845/46/47 Densitometerspecification

Brochure No.

B1026

В1024

Entrained gas densitometer B1018

7826 Densitometerspecification B1019

7812 Gas densitometerspecification В1022

3096 Specific gravitymeter specification В1023

7945 Signal converterspecification B1200

Solartron124 Victoria RoadFarnboroughHants., GUM 7PWUKTel: +44(0)1252376666Fax: +44 (0) 1252 547384

Email: trn_info@solartron.com

Solartron19408 Park Row, Suite 320HoustonTexas 77084USATel: +1 713-398-7890Fax: +1 713-398-7891

Web: http://www.solartron.com

SolartronBlock 5012, Ang Mo Kio Ave 5#04-11 TECHplacellSingapore 569876Republic of SingaporeTel: +65 482 3500Fax: +65 482 4645

Solartron Transducers pursues a policy of continuous product development and product imrovement. The specifications in this document may therefore be changed without notice.

Part No. В1025