High Precision Inventory Tank Gauging System

TankRadar L/2ExDISPLAYMODE©Technical DescriptionTemperature measurementProduct temperature is an important parameter foraccurate custody transfer and inventorymeasurement in liquid bulk storage tanks. Highquality Multiple Spot Thermometers (MST) can beincluded in the Rex system delivery as an essentialpart.The Multiple Spot Thermometer (MST) measuresthe temperature with a number of Pt 100 spotelements placed at different heights to provide atank temperature profile and an averagetemperature. Only the elements that are fullyimmersed are used to determine the producttemperature. The spot elements are placed in aflexible gas tight protection tube made fromconvoluted stainless steel. A flange can be attachedto a top fitting and the tube can be anchored to thebottom.API chapter 7 recommends minimum one elementper 10 feet (3 m) tank height for custody transferapplications.The Multiple Spot Thermometer is easy to install,even if the tank is in service. In pressurized tanksthe MST can be installed in a closed thermowell sothat it can be removed for service or inspectionwhile the tank is in operation. For LPG tanks singlespot temperatures sensors in thermowells are used.Temperature sensors can be connected in two waysto the RTG:• Directly into the RTG with common returnconnection (up to six temperature elements)•Via the DAU (up to 14 temperatureelements)A water bottom sensor can be integrated in theMST, se page 34.RTGDAURTGMultispotThermometerMultispotThermometerAnchor weight or alternativelya loop with steel wire pulledthrough and to top of tank.Anchor weight or alternatively aloop with steel wire pulledthrough and to top of tank.Up to 6 temperature elements can be connected directly tothe radar gauge.When the number of temperature elements is above 6 they areconnected via a Data Acquisition Unit. Maximum 14 temperatureelements can be connected.22