JPS5824317B2 - How to prevent ship ballast water from freezing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing freezing of ballast water in ships equipped with ballast tanks.

When a ship equipped with a ballast tank sails in a cold region with severe outside air conditions, such as water or sea, there is a risk that the ballast water in the tank may freeze. Generally, a heating coil was installed to heat the ballast water in the tank using high-temperature steam.

However, in the case of such a heating method, a heating coil must be installed inside the ballast tank and high-temperature steam must be supplied from the boiler to this heating coil, which makes the equipment difficult and expensive. However, since a boiler with a large capacity was required, the fuel cost for firing this boiler was also high.

Moreover, the heating coil is usually installed near the bottom of the ballast tank to avoid problems caused by fluctuations in the ballast water level, so most of the heat from this coil is transmitted through the bottom and side plates of the ship. There was also the problem that the water escaped into the seawater and was not very effective at heating the water in the upper part of the tank, where freezing is most likely.

This invention was made in view of the above circumstances, and its purpose is to reliably prevent freezing of ballast water by circulating the ballast water of ships operating in cold regions using ballast pumps, etc. The purpose is to provide a prevention method and easily solve the various problems described above.

Hereinafter, one embodiment of the method of this invention will be described in detail with reference to the drawings.

Figure 1 shows that a ship has a ballast tank 2 connected vertically and integrally on the side of the hull 1.
The ballast water W inside the tank is sucked out by the bell mouth 3 located at the bottom of the tank below the water level a, and discharged out of the ship from the overboard discharge port 5 of the hull 1 by the operation of the pump 4. A corresponding amount of seawater is taken in from the sea chest 6 installed near the bottom of the ship, and fed into the tank from the upper water injection pipe 8 of the ballast tank 2 by the operation of the pump 7, thereby circulating the ballast water in the ballast tank 2. This prevents ballast water from freezing during navigation in cold regions.

Note that it is natural that the amount of ballast water discharged by the pump 4 and the amount of seawater introduced by the pump are equal, but the flow rate and flow velocity are controlled to appropriate values so that the ballast water in the ballast tank 2 does not freeze. Ru.

Of course, the above-mentioned freezing prevention of ballast water is not only due to the flow of this water, but also due to the seawater freezing temperature (-1° to -2°C).
This is largely due to the fact that seawater, which is several degrees warmer than normal, is taken in from near the bottom of the ship and circulated through the upper part of the tank.

Fig. 2 shows a modification in which the method of the present invention is applied to a ship having a structure in which the ballast tank is separated into the top side and double bottom of the hull 1, in which a top side tank 2a and a double bottom tank 2b are used. are connected by a communication pipe 9, and a double bottom tank 2 is connected.
The ballast water W in the ballast tank 2 is sucked by the bell mouth 10 and the ribbon pump 11, and is fed to the top side tank 2a from the upper water injection pipe 12, thereby circulating the ballast water W in the ballast tank 2 at a predetermined flow rate and flow rate. This prevents the ballast water W from freezing during navigation in cold regions.

Since the method for preventing freezing of ballast water according to the present invention is as described above, the ballast water is supplied to the seawater below the stagnant water level, which is several degrees higher than the seawater freezing temperature (-1° to -2°C), or to the upper part of the ballast tank. By circulating the ballast water, freezing of the ballast water can be reliably prevented.

Moreover, there is no need to install a heating coil inside the ballast tank or a large-capacity boiler as in the past.
It is possible to simplify the equipment, reduce costs, and save fuel consumption.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the invention, and FIG. 2 is an explanatory diagram showing another embodiment of the invention. 1... Hull, 2... Ballast tank, 2a... Top side tank, 2b... Double bottom tank, 3...
Bell mouth, 4,7.11...pump, 5...-overboard outlet, 6...sea chest, 8/1/1
2...Tank upper water injection pipe, W...Ballast water.

Claims (1)

[Claims] 1 Either the ballast water in the ballast tank is sucked out from the bottom of the tank below the water level and fed and circulated above the ballast tank, or the ballast water sucked out from the bottom of the ballast tank is discharged overboard and the amount of water discharged is determined at the same time. A method for preventing freezing of ballast water on a ship, characterized in that the freezing of ballast water is prevented by taking in an amount of seawater corresponding to the amount of seawater (force near the bottom of the ship) and supplying and circulating it above a ballast tank.