temperature, vapour pressure and high-level alarm systems using Supervising Computing and Data Acquisition Systems and the Programmable Logic Control Platform. Selma’s full product range includes main switchboards, engineroom monitoring and alarm consoles, boiler automation systems, dewatering control systems and navigation consoles. Krohne Skarpenord of Norway has recently
delivered its Cargomaster Tank Monitoring System with Optiwave level radars to Brave Maritime’s newbuilding at Daewoo Shipbuilding & Marine Engineering in South Korea. The system will be designed to fulfil Chevron’s regulations for oil transportation, which include redundant monitoring of cargo tanks. By using the radar’s high accuracy for
ullage measurements in the upper tank levels, operators will have accurate readings for topping off tanks. Further down in the tank where the radar beam has problems recognising a level, the pressure sensor will provide a correct tank level all the way down to the tank bottom. A switch point between the two different sensors has been programmed in the Cargomaster software. The system will use the radar as the primary level instrument above the switch point, and the pressure/ level sensor below the switch point. Together, the radar and pressure sensor will also calculate the cargo density. A 6 + 6 order for tank monitoring
systems has also been received for VLCCs on order to NITC in China due for delivery this year and next. Six VLCCs will be built at Dalian Shipbuilding and six at Shanghai Waigaoqiao
Shipbuilding. The
systems are extensive, and include full redundancy on the monitoring side. Optiwave Cargo Level Radars will be installed on all 15 cargo tanks. The two slop tanks will be equipped with a hybrid level gauging solution combining level radar with a pressure sensor close to the tank bottom to secure level readings in the bottom area as well as density calculations of the slops. The deliveries will also include subsystems from Krohne’s partners Scanjet Macron and Vimex. Krohne reports good market uptake
for its hybrid solution. References include a delivery for a small deck tank on a chemical tanker necessary because a tank radar will pick up interference in the radar wave propagation caused by the cylindrical tank shape. The company says installing a stillwell with all its cleaning issues is not a good
www.tankershipping.com Top unit locking screw
IGP-sensor mounted on radar
option on chemical tankers. Rather, a pure cargo level pressure sensor installation or an Optiflex 4300 C guided level radar installation will provide good monitoring. Hanla of Korea provides cargo tank
measuring systems, remote sounding systems and valve remote control systems. Its cargo monitoring systems are suitable for all types of tankers as well as for FPSOs. Hanla’s remote sounding systems are configured with a level gauging system that is integrated online through the communications unit of the cargo monitoring system or displayed on the level indicator for ballast or engineroom tanks. The company’s range of level gauges includes electro-pneumatic, electric pressure, air purge and microprocessor-controlled models. Jowa USA provides level gauging solutions based on Metritape, a non-mechanical,
Stainless steel protection cover
Local
calculation of level data
Touch-
screen with 4-button operation
Stainless steel housing
continuous level sensor which the company claims offers clear advantages over other level technologies, especially in thick, sticky liquids that cause mechanical level gauges to seize. The Metritape resistance-tape level sensor features full height, independent high alarm, three point temperature and inert gas pressure monitoring in a single deck penetration with a single cable run per tank, which reduces installation costs. The Metritape sensor extends into the cargo well, providing gauging below tank bottom and speeding up discharge time. The flexible sensors follow the contour of J-shaped ballast tanks for high-performance level detection at an affordable price, says Jowa. No tank entry is required for installation or service and the equipment is virtually maintenance-free. The Metribeam tank radar system can be used for cargo tanks and combined with resistance-tape for ballast, service tanks and draft. The Metribeam tank radar is used to gauge petroleum products and chemicals with temperatures of up to 200°C. Its high signal-to-noise ratio combined with the 24 GHz high frequency electromagnetic wave makes it one of the most accurate and reliable tank gauges in the marine market, according to Jowa. The Metribeam has a measuring range of 0.35 to 50m, making it suitable for any vessel. The Metrimeter is a single tank instrument that directly interfaces with Metritape level and level/ temperature sensors. It provides a 6-digit alphanumeric display, a 40-point bar graph display and six alarm and fault indicators. In addition, it may be used as a slave meter when connected to other systems. Through an extensive menu system, the meter may be set up and configured to suit individual requirements. The Metrimeter can do full height, overfill alarm and two temperature readings. As one is used for each tank, Jowa says it can be very cost effective for shipowners to retrofit if they want an accurate level gauging system for fuel tanks. NDT International of the US
Radar antenna
Washing connection protected by a ball valve
Skarpenord’s Cargomaster Tank Monitoring System with Optiwave level radars
supplies the PLI-1 portable Ultrasonic Liquid Level Indicator made by Class Instrumentation of the UK. The unit’s features include automatic calibration, no tuning controls, dry sensor application and a special power booster for poor condition tanks and cylinders. The unit is accurate to 1.5mm. TST
Tanker Shipping & Trade I October/November 2011 I 39
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