Dieselpropelled Vessels

A propulsion diesel engine that operates below approximately 300 rpm and is directly connected to a propulsion shaft is usually classified as a slow-speed engine. Diesel engines that are connected to propulsion shafts through reduction gears and have maximum operating speeds below 900 to 1200 rpm are typically classified as medium-speed engines, and engines that operate above 900 to 1200 rpm and are used with reduction gears are generally classified as high-speed engines.

engine freshwater cooling pumps A pump is ordinarily used to circulate freshwater through jackets in a propulsion diesel engine's cylinders and cylinder heads, the engine's turbocharger, and, on some vessels, an evaporator where the jacket water provides heat to produce fresh water. The jacket water may also pass through the engine's lubricating-oil and charge-air coolers. In addition, a heat exchanger in which the jacket water is cooled by either freshwater or seawater is frequently included in the system. Alternatively, this heat exchanger is sometimes eliminated when a vessel has a central freshwater cooling system. Instead, some freshwater from a separate low-temperature loop is admitted into the high-temperature jacket-water loop where it mixes with and cools the hot jacket water. An additional heat exchanger that can be used to preheat the jacket water prior to engine start-up is often provided as part of a main engine's jacket-water system.

The pumps that circulate cooling water through a propulsion diesel engine are frequently called jacket-water circulating pumps. Alternatively, however, they may be referred to as high-temperature freshwater cooling pumps on a vessel that has a central freshwater cooling system. Two vertically or horizontally mounted single-stage centrifugal pumps that are each sized to meet normal full-load requirements are often provided for each propulsion engine. Although each pump may be driven by an electric motor, when used with a high- or medium-speed propulsion engine, one of the pumps is often mounted on and driven off the engine. An elevated tank is ordinarily included in the system to allow for any thermal expansion of the water and to maintain a positive pressure at the pump suction.

Separate electric-motor-driven pumps may be used to circulate fresh water through a propulsion engine's pistons when they are water-cooled. Although single-stage centrifugal pumps are often used in this application, vertical turbine pumps that are submerged in the piston-cooling-water drain tank are used on some vessels. When required by the engine design, an additional pair of electric-motor-driven centrifugal pumps is provided to circulate fresh water through an independent loop that cools the main-engine fuel valves or injectors.

engine seawater cooling pumps On some vessels, single-stage centrifugal pumps are used to supply seawater to diesel-engine charge-air, lubricating-oil, and jacket-water coolers. Two pumps that are each sized to meet normal full-load requirements are often provided for each propulsion engine. Although both seawater-cooling pumps may be driven by electric motors, when a medium- and high-speed diesel engine is used, one pump is sometimes attached to and driven by the engine.

fuel-oil supply and booster pumps Fuel-oil (FO) pumps used for diesel engines should be suitable to handle any of the various grades of fuel that may be burned in a vessel's engines, which can often include both light distillates that are used during maneuvering and heavy residual oils that are used while underway at sea. When heavy fuel oil is supplied to an engine, it must generally be heated to reduce its viscosity.

A FO booster pump typically takes suction either directly from a diesel-propelled vessel's daily service tanks or from a separate mixing tank and supplies fuel oil to the main-engine injector pumps. Two multiple-screw- or gear-type fuel-oil booster pumps that are each capable of meeting full-power requirements are often provided for each propulsion engine. Both FO booster pumps may be electric motor driven. Alternatively, however, when a medium- and high-speed diesel engine is used, one FO booster pump is sometimes attached to and driven by the engine. Also, in some high-temperature heavy-fuel-oil systems, a pair of electric-motor-driven screw- or gear-type FO supply pumps that operate upstream of and in series with the FO booster pumps are located between the service tanks and the mixing tank. More oil is typically delivered to an engine than the amount required for combustion, and the excess oil is ordinarily returned to the service or mixing tank through a recirculation line. Strainers, filters, flow meters, and heaters are also frequently installed in the FO service system.

LUBRICATING-OIL PUMPS The main-engine lubricating-oil (LO) pump typically removes lubricating oil from a sump located below a propulsion engine and discharges the oil to the engine's bearings, governor controls, turbochargers, and, when they are cooled by oil, the engine's pistons. Strainers, filters, and a cooler are also usually included in a LO system. Two main LO pumps that are each capable of delivering the oil required during normal full-load engine operation are usually provided for a propulsion engine. Vertically or horizontally mounted multiple-screw and gear pumps are frequently used in this application. Although both pumps may be driven by electric motors, one pump is sometimes attached to and driven off a medium- or high-speed engine. Alternatively, some vessels have electric-motor-driven vertical turbine pumps that are submerged within the LO sump installed. A device that sounds an alarm following a failure of the LO system is normally provided.

When a vessel is propelled by a crosshead-type diesel engine, some of the oil discharged by the main LO pump is often directed to the suction-side of a lower-capacity rotary-type booster pump that supplies oil to lubricate the engine's crosshead bearings. In addition, a separate low-capacity rotary pump is frequently required to fill a head tank that supplies a different grade of oil to lubricators that inject the oil into each of a crosshead engine's cylinders. Also, with some designs, a separate pair of rotary pumps is required to supply lubricating oil to the engine's camshaft bearings.

In addition to the pumps that supply lubricating oil to propulsion engines, separate rotary pumps are generally used to supply lubricating oil to reduction gears and their bearings on vessels propelled by medium- or high-speed engines.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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