Liquid loading assembly for filling a ship-hold or tank
A liquid loading assembly for filling a ship-hold or tank with a volatile liquid, includes an oil supply conduit, fluidly connected to the tank, the outlet end of said conduit extending vertically within a dropline. The dropline extends from a lower dropline end positioned below the outlet end of the oil supply conduit to an upper dropline end positioned above the outlet end of the oil supply conduit, the lower dropline end being at least partially closed by a valve. The valve is arranged to open gradually up to a maximum aperture in response to one of i) increased pressure on the valve and ii) a level of liquid above the valve.
1 . A liquid loading assembly for filling a ship-hold or tank ( 12 ) with a volatile liquid, the assembly comprising:
an oil supply conduit ( 11 ), fluidly connected to the tank ( 12 ), an outlet end ( 111 ) of said oil supply conduit ( 11 ) extending vertically within a dropline ( 13 ) wherein said dropline ( 13 ) extends from a lower dropline end ( 131 ) positioned below the outlet end ( 111 ) of the oil supply conduit to an upper dropline end ( 132 ) positioned above the outlet end ( 111 ) of the oil supply conduit, the lower dropline end ( 131 ) being at least partially closed by a valve ( 14 ), said valve opening gradually up to a maximum aperture in response to one of i) increased liquid pressure on the valve ( 14 ) by liquid in the dropline ( 13 ) above the valve ( 14 ) and ii) a sensed level of liquid within the dropline ( 13 ) above the valve.
2 . The liquid loading assembly of claim 1 , wherein the outlet end ( 111 ) of the oil supply conduit ( 11 ) is arranged at a vertical distance (OSC V ) of at least 4 meters above the lower dropline end ( 131 ).
3 . The liquid loading assembly of claim 1 , wherein the outlet of valve ( 14 ) at the bottom end of the dropline is localized in the range between 1 and 3 meters above a bottom wall ( 121 ) of the tank ( 12 ).
4 . The liquid loading assembly of claim 1 , wherein the valve ( 14 ) comprises a closure member opened by at least one of the following mechanisms, i) a pressure spring acting against the pressure of the liquid in the dropline ( 13 ), and ii) a level sensor in communication with a control system arranged to open the closure member to a degree sufficient to hold the liquid level at a mainly constant level in the dropline ( 13 ).
5 . The liquid loading assembly of claim 4 , wherein the mechanism involves a pressure spring connected to hold the closure member in a closed position when the dropline is empty and selected with a spring force unable to hold the closure member in a closed position when the dropline is filled with a volatile fluid of density higher than 0.6 kg/l to a level above the outlet end ( 111 ) of the oil supply conduit ( 11 ).
6 . The liquid loading assembly of claim 1 , wherein the valve ( 14 ) includes a closure member defining a limited open fluid passage in a closed position.
7 . The liquid loading assembly of claim 1 , wherein the maximum aperture and a closure force of the valve hold the fluid to be filled at a constant level within the dropline ( 13 ) during filling, said level depending upon the density of the fluid.
8 . The liquid loading assembly of claim 1 , comprising a bypass conduit ( 30 ) with an inlet from the dropline ( 13 ) adjacent to a top wall ( 122 ) of the tank ( 12 ), and an outlet proximate a bottom wall ( 121 ) of the tank ( 12 ), or into a common distribution pipe ( 51 ).
9 . The liquid loading assembly of claim 1 , in which an assembly ( 16 ) with a check valve ( 17 ) is arranged between the upper dropline end ( 132 ) of the dropline ( 13 ) and the tank ( 12 ) in order to allow vapour to flow from the tank to the dropline but not from the dropline to the tank.
10 . The liquid loading assembly of claim 1 , wherein the valve ( 14 ) is connected to a conduit ( 18 ) having an outlet end proximate a bottom ( 121 ) of the tank ( 12 ).
11 . The liquid loading assembly of claim 10 , wherein the conduit ( 18 ) is connected to a distribution pipe ( 51 ) extending through a plurality of tanks.
12 . The liquid loading assembly of claim 1 , wherein the outlet end ( 111 ) of the oil supply conduit ( 11 ) is arranged within the tank ( 12 ).
13 . The liquid loading assembly of claim 1 , wherein the outlet end ( 111 ) of the oil supply conduit ( 11 ) and the dropline ( 13 ) are arranged outside the tank while an outlet conduit ( 41 ) from the valve ( 14 ) is connected to the tank ( 12 ) proximate a bottom wall ( 121 ) thereof.
14 . The liquid loading assembly of claim 1 , wherein the upper end of the dropline ( 13 ) extends above a top wall ( 122 ) of the tank ( 12 ).
15 . The liquid loading assembly of claim 1 , wherein the dropline ( 13 ) has a height extending above the outlet end ( 111 ) of the oil supply conduit ( 11 ) allowing a height of liquid in the dropline ( 13 ) corresponding to a depth of the tank ( 12 ).