High Precision Inventory Tank Gauging System

Technical DescriptionAccuracy enhancementTo enhance accuracy further, TankRadar Rex hassome built-in unique features:Temperature controlTankRadar Rex gauges are designed to operate inall climates. The gauge is continuously controllingthe temperature of the electronics and keeps itconstant. This is one of the reasons for the highaccuracy and the 65 years of mean time betweenfailure (MTBF) for the gauge.Antenna design with no horizontal surfaces according to the AmericanPetroleum Institute Standard (API ch. 3.1B).Digital referenceA radar gauge needs an internal reference to makethe radar sweep absolutely linear. Each deviationfrom the linearity produces a correspondinginaccuracy. To achieve highest precision, SaabTankRadar Rex uses a digital crystal oscillator. Thisgives the most stable reference that is available withtoday’s technology.TankwallNotacceptedTankwallAcceptedDrip-off means no condensationIf the antenna has an inclined polished PTFEsurface(Teflon ® ) where the microwaves are emitted,it will be less susceptible to condensed water orproduct. The drops of condensation will not coatthe active part of the antenna. In this way the radarsignal will be less weakened resulting in higheraccuracy and better reliability.LiquidLiquidGauges emitting microwaves with circular polarization can be installedcloser to the tank wall.Measurement close to tank wallA standard manway (or flange) is normally 0.3-1 m(1-3 feet) from the tank wall. Both the Saab RTG3920 Horn Antenna Gauge and the RTG 3930Parabolic Antenna Gauge are specially designed tobe mounted close to the wall.The RTG 3920 Horn Antenna Gauge radar signal ispolarized so that the direct reflection from theliquid surface is the only detectable reflection. Anywall disturbance will be blanked out. The RTG 3930Parabolic Antenna has a narrow radar beam due tothe large 20-inch antenna diameter resulting in asmall and uncritical wall echo.10