This paper describes a new generation of stand-alone type radar level gauges that has recently been developed. It discusses the measuring principle and some design features used to make installation easier on existing tank plants. Various types of storage tank applications are described although special emphasis has been put on tank gauging in pressurized tanks with Liquefied Petroleum Gas (LPG).
Non-contact level gauging offers substantial advantages in LPG storage tanks. These tanks are a specially demanding application as the pressurized condition does not give any possibility for in-tank maintenance or hand dip checks.
The radar method allows the gauge to be totally separated from the tank contents and enables maintenance without tank opening. The new version of the system has been put into operation in a number of refineries and tank terminals. It is based on intelligent radar transmitters mounted on top of each tank. Also temperature sensors, spot or average, are connected to the radar transmitters. The installations include transmission of finished level and temperature data on a two-wire field bus. The radar method was first used for tank gauging in 1975 for marine applications on tankers. Today around 50% of all new tankers are equipped with this type of instrument. The first shore-based installation in the oil industry was made on a BP refinery in 1984 and a total of about 3000 gauges have been supplied for refineries, tank terminals and the chemical industry.
Paper Delivered by:
H Westerlind (Saab Tank Control, Sweden)
Gastech Paris 1993