Radar level transmitters

Radar level transmitters and gauges use electromagnetic waves, typically in the microwave bands to make a continuous liquid and some solid level measurements. The radar sensor is mounted on the top of the vessel and is aimed down, perpendicular to the liquid surface. Most tank-farm gauges are operated on the FMCW principle (Figure 3.121). Other gauges and transmitters, particularly the lowest-cost units, are operated on the pulse principle. Both principles are fundamentally based on the time of flight from the sensor to the level of the surface to be measured. In the FMCW method, this time of flight is tracked on a carrier wave in the pulse method, it is the echo return. 

Microwave/radar level transmitters 5% Three devices are mounted with separation and utilize two dissimilar technologies... 

Radar level transmitter Fails to detect high loch level 1.1E-06 3.6E-07 4.7E-07 82% Manufacturer s data adjusted... 

Vega Controls Ltd. Technical Bulletins 2.14763 and 2.I472S (August 1992). Ultrasonic and radar based level transmitters. 

On hard-to-handle services, such as the fluidized-bed level measurement in combustion processes, there is little choice but to use radiation gauges. On slurry and sludge services, d/p units with extended diaphragms eliminate the dead-ended cavity and bring the sensing diaphragm flush with the inner surface of the tank. Other level transmitters that can be considered for hard-to-handle services include the capacitance/RF, laser, radar, sonic, and TDR types. 

FMCW radar level gauges are the primary tank farm radar devices because of the inherent accuracy. Pulse transmitters are not suitable for tank farm inventory and custody transfer applications. The combination of foam and low-dielectric material can cause errors or provide an insufficient signal strength on the return signal. 

Microwaves and Radar yes yes liquids, powders, granular solids. Action very similar to ultrasonic signals. Has been employed for discrete sensing. Pulsed energy used in transmitted or reflected inodes. Transmitter and receiver can be mounted outside the vessel. Very useful for determining mean levels io closed vessels under difficult conditions, e.g. in cases of high turbulence, in the presence of vapour or condensate, or where there is encrustation of surfaces with deposits. Typical accuracies are of the order of 0.2 per cent FSD 1. 

Hybrid inventory measurement system. The hybrid inventory measurement system (HIMS) combines the most modern level gauging techniques with hydrostatic tank gauging (Figs. T-13 and T-14). It utilizes an advanced radar or servo level gauge for accurate level measurement, with a smart pressure transmitter (PI) and a temperature measurement instrument. On nonatmospheric tanks a second transmitter for the vapor pressure compensation is required. 

Advanced servo gauges and radar gauges can be provided with an interface board that communicates directly with the smart pressure transmitter. The result is a unique and very complete measurement providing level, interface levels, product-water interface levels, average density, average temperature, vapor temperatme, and alarms. 

Hybrid inventory measurement system. HIMS are also based on the integration of smart pressure transmitters. Modem level gauges, either servo or radar, provide the possibility for direct interfacing to smart pressure transmitters. HEMS opens the ideal route to total tank inventory systems, measuring all tank parameters via... 

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