The deck water seal is the principal barrier; a water seal is fitted that permits inert gas to be delivered to the deck main but prevents any backflow of cargo gas, even when the inert gas plant is shut down; it is vital that a supply of water is maintained to the seal at all times, particularly when the inert gas plant is shut down; in addition, drains should lead directly overboard and not pass through the machinery spaces; one of three principal types of design may be adopted.
Types of Deck Water Seal:
Wet type
This is the simplest type of water seal; when the inert gas plant is operating, the gas bubbles through the water from the submerged inert gas inlet pipe, but if the tank pressure exceeds the pressure in the inert gas inlet line, the water is pressed up into this inlet pipe, thus preventing backflow; the drawback to this type of water seal is that water droplets may be carried over with the inert gas, which, although not impairing the quality of the inert gas, could increase corrosion; a demister should, therefore, be fitted in the gas outlet from the water seal to reduce any carry-over.
Semi-dry type
Instead of bubbling through the water trap, the inert gas flow draws the sealing water into a separate holding chamber by venturi action, thus avoiding or at least reducing the amount of water being carried over; otherwise this seal is functionally the same as the wet type.
Dry type
In this type, the water is drained when the inert gas plant is in operation (gas flowing to the tanks), and filled with water when the inert gas plant is either shut down or the tank pressure exceeds the inert gas blower discharge pressure; filling and drainage are performed by automatically operated valves controlled by the levels of the water seal and drop tanks and by the operation of the blowers; the advantage of this type is that it prevents water carry-over; the drawback could be the risk of failure of the automatically controlled valves that may render the water seal ineffective.
Collections Of Sea-based and Land-based Related topics, Inspirational Thoughts, Ideas And Information For Filipino And International Seafarers. All that matters for the family, people and friends.
Wednesday, 20 May 2015
Monday, 4 May 2015
Filipino Seafarers
To all Filipino Seafarers please visit Maritime Industry Authority (MARINA) official website for more details and updates.
Monday, 16 March 2015
Tuesday, 17 February 2015
Wednesday, 11 February 2015
ADVANCED TRAINING FOR OIL TANKER CARGO OPERATIONS
The mandatory minimum requirements for the training and qualifications of Masters, Chief Engineer Officers, chief mates , second engineer officers and any person with immediate responsibility for loading, unloading and care during transit and handling, tank cleaning or other cargo related operations on Oil tankers as specified in Regulation V/1-1 paragraph 3 of the International Convention on Standards of Training, Certification and Watch keeping for Seafarers 1978, as amended. The competences are stipulated in the STCW 2010 table A-V/1-1-2
To show consistency and adherence to STCW 2010, as given in STCW Code Chapter V, Table A-V/1-1-2.
To show consistency and adherence to STCW 2010, as given in STCW Code Chapter V, Table A-V/1-1-2.
Monday, 10 November 2014
Saturday, 8 November 2014
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