Air Ejector works on the principle of convergent or divergent nozzle as it provides the venturi effect at the point of diffusion as the tube gets narrows at the throat the velocity of the fluid increases and because of the venturi affect it pressure decreases, vacuum will occur in the diffuser throat where the suction line will be provided.
An air ejector which uses the high pressure motive fluid such as air or steam to flow through the convergent nozzle the function of the convergent nozzle is to convert the pressure energy of the motive fluid into the velocity energy.
Air ejectors on a ship help in removing air blocks from the ship's feed water system. There are several types of air ejectors used on ships. The article describes as to how an air ejector works and what are its important parts are. Removing any amount of trapped air from working systems on a ship is an essential task. Trapped air is mainly found in systems which deal with carrying steam and vapours. Air in the system not only leads to loss of differential pressure across the system but also to many harmful conditions in the long term. One such system on ship wherein air is commonly found is the feed water system. To eradicate the problem of trapped air from feed water system, air ejectors are used.
Air ejector is an essential component of any type of feed system on the ship. As the name suggests, the equipment completely removes the air from any system and also draws out the vapours released from the condensing steam in the condenser.
Presence of air in the system leads to several detrimental effects on the boiler. Corrosion is one such effect that in long run results is failure of the boiler from the inside. Also, the accumulation of air inside the condenser affects the condensing process, which results in the production of back pressure. The back pressure thus generated leads to increase in exhaust steam pressure and reduction in thermal efficiency of the plant.