RF Admittance Continuous Basics Theory of Operation AMETEK Drexelbrook 205 Keith Valley Road Horsham, PA 19044 (215) 674-1234 www.drexelbrook.com This presentation will discuss the theory of how an RF Admittance Continuous Level.

Continuous RF Admittance Theory

Capacitance Transmitters -- how they work L1 L2 gnd Amp chopper LLFS C probe 2 terminal cable 2 terminal probe 100kHz Osc. Power supply + - 4-20 mA step span fine span step & fine zero HLFS Second Question: Who can tell me what they think will happen as the level rises on the sensing element? What could happen if: A) Gland C changes? B) Coax C changes? 5

Capacitance Instruments.... the effects of a coating 100% 0% 70% Highly Conductive Liquid 50% 16

The Anatomy of a Coating Small amounts of RF current flow (both Resistive and Capacitive) due to the Coating Teflon Insulation Coating probe rod Xc High Resistance Tank Wall R Little to No Resistance 17

Problems with Capacitance No coating rejection Coax cable can affect output / calibration Coax Cable must be short

Capacitance Disadvantages Capacitance devices can only measure capacitive current flow. Conductive coatings generate a resistive current flow from the coating in addition to capacitive current flow from the bulk mass of the level. Capacitance systems will read the additional resistive current flow and produce level reading that are higher than the actual level due to this additional increase in current flow

RF Admittance Transmitters -- how they work power Amp chopper HLFS LLFS C probe step & fine zero 3 terminal cable 2 terminal probe 100kHz Osc. 4-20 mA step span fine span drive 100 kHz 1:1 Cote Shield Amplifier + - How is an Admittance Transmitter different than a Capacitance Transmitter? What does the Chopper drive circuit do? Where do the resistive currents come from? 22

RF Admittance Advantages Advantages over Capacitance: Ignores Coatings on sensor Coax cable does not affect output / calibration Coax Cable can be 100 ft. (30 m)

RF Admittance Advantages System output unaffected by: Process material coating the sensor Conductivity changes Temperature changes Pressure changes Specific Gravity changes Density changes Highest accuracy in short span measurements RF Admittance accuracy is +/- 1% of calibrated span No moving parts to break or wear out

Laptop PC Calibration Software makes commissioning and configuration easy

Laptop Software Version 6.0

RF Admittance Continuous Level Products

RF Technology used in Liquid/Liquid Interface

Oil / Water Interfaces

Free Water Knock-out Automatic Well Tester is a small vessel that accepts the Gross Production from one well (30% - 90% water). This is nothing more than a holding tank that allows initial emulsion separation, and interface is controlled by RF transmitter controlling a dump valve. AWT oil output goes to FWKO for further separation. FWKO is typically 12 ft. dia. X 60 ft. long. Emulsion enters with about 60% water and may exit with about 30% water.

Heater Treater Gravity separation that uses Heat and Chemicals to further break down emulsions. Typically mechanical elements which aid in the coalescing of the water droplets. Dry Oil is skimmed off over a weir.

Stock Tank Where Dry Oil is stored before it goes to the LACT unit and pipeline.

Skim Tank Where wastewater from earlier separation vessels goes to allow recovery of entrained oil.

Interface Level Typical Rag / Emulsion Make-up RF Technology Frequency Advantage: Repeatable indication of electrical cross over between continuous conducting to continuous insulating emulsion phase Insulating Phase Rag Layer: Optical Interface VS. Electrical Interface Aqueous Phase

Desalter Interface System + - Electrostatic Grids Inactive Section Active Section Oil Brine AC Interference Filter Smart Desalter Interface Transmitter Integral or Remote 4-20mA HART or Honeywell protocol 1 ft. 1 ft. 1 ft. clearance from Grids to Probe has been found to provide the best immunity to signal interference.