Friday 11 May 2012

Air Ejectors

Air Ejectors
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FUNCTION

Air ejector units are generally of the steam jet type. Although electrically powered units offer the advantage of ease of installation and slightly improved operating efficiency their maintenance requirements has ensured that the most common type on larger installations are steam powered Their primary function is to remove non- condensible gases from the condenser
After passing through the nozzle the high velocity stream jet entrains air and vapour , compresses it, and the mixture passes to a condenser section were it is cooled. The air with any uncondensed steam and vapour passing to the second stage were further compression of the air takes place.
Depending upon the number of stages of the air ejector, the air is now discharged to atmosphere or to a final stage and then to atmosphere.
The condensers are of the surface type and are cooled by condensate, in this way acting as a feed heater.
Either, two complete units or two ejectors mounted on one condenser are used , nozzle diameters are very small typically 1.2 to 4.7 mm and are liable to wear, abrasion and blockage.
When manouevring or at rest provision must be made to ensure that there is adequate flow of condensate through the condenser to provide cooling . This is achieved by means of a recirculating v/v which leads condensate from the outlet of the air ejector condenser outlet ( and other low pressure feed heaters such as an evapourator ) back to the main condenser. The opening of this v/v should be limited as it leads to a loss of plant efficiency.

Electric Powered

Electric Air Ejector The position of the cooler can vary; either as shown, incorporated into the tank or on the suction side of the pump.

2 comments:

  1. I am the author of most of the work on your website against which you are making financial gain. If you do not gain permission or remove it I will take further action. My site is non-commercial, I note you have placed content from marinediesels.info which is a commercial site, you are in breach of his copyright and as such ne may not be as generous in allowing you time to remove his work before taking further action.
    note you have incorrectly ripped off my site showing a HP feed heater on this page
    brian

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