New shifting clutch combination for hybrid tugs

(Herne, April 2015) The German couplings expert VULKAN showcased at the Tugnology, which takes place at the London Lancaster Hotel from 19th to 20th May 2015, the new TDS Plafrix, which is specially developed for use in hybrid tugs.

The industry is challenged by the growing environmental awareness, the increased needs to avoid pollution and increasing fuel prices.

Especially for harbour tugs a feasible solution appears to lie in their operating profile. In most diesel driven tugs the main engines operate only two percent of the time at maximum power and about 80 percent of the time at less than 20 percent of the nominal power. This makes these tugs almost predestinated for hybrid propulsion. Due to the combination of electrical power for the low load phases of operation and the full power of the diesel engines, smaller engines with less consumption can be installed.

New shifting clutch combination: TDS Plafrix

To separate diesel engine end electrical motor VULKAN is offering the TDS Plafrix, a clutch coupling combination that has been designed especially for this configuration.

Considering the mentioned operational profile a VULASTIK L 4010 can be loaded up to 14.46 kNm for this application. By use of an appropriate stiffness the torsional vibration behavior of the installation can be optimized and the sound level and comfort on board can be increased. The integrated, pneumatically actuated clutch with radial air supply, a specially designed PLANOX 184/00 by DESCH, is capable to transmit a nominal torque of 30 kNm. The use of dry running organic friction discs minimizes the number of discs needed and leads not only to a weight, but also to a drag torque reduction, which is further reduced by separating the friction discs by springs when declutched.

To transmit the full torque at a speed of 1.800 rpm and to engage the clutch at a differential speed of up to 650 rpm pressurized air of 5.5 bar is needed. This medium was selected considering a “clean ship”-thinking. In case of a leakage there will be no spoiling of the engine room with oil as in hydraulically activated clutches. Moreover, compressed air is assumed to be available on board as standard.