GB1561664A

GB1561664A - Cargo ships having ventilation devices

Info

Publication number: GB1561664A
Application number: GB47204/76A
Authority: GB
Original assignee: Machinefabriek en Handelmaatschappij Winel BV
Current assignee: Machinefabriek en Handelmaatschappij Winel BV
Priority date: 1975-11-13
Filing date: 1976-11-12
Publication date: 1980-02-27
Also published as: NL7612579A; JPS5275791A; NO763854L; FR2331493A1; DE2553865A1

Description

(54) IMPROVEMENTS IN AND RELATING TO CARGO SHIPS HAVING VENTILATION DEVICES (71) We, MACHINEFABRIEK EN HANDEL MAATSCHAPPIJ "WINEL" b.v., a Dutch Company of Havenkade 16, Assen, Holland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a cargo ship having a tank ventilation devices of the type comprising a ventilation nozzle connected to the ventilation tube of a tank or storage hold for liquid.

The known conventional embodiments of these devices with which ships are equipped are frequently, as experience has proved, a source of pollution by reason of the overflow of fuel oil from the tank which occurs in its filling. In order to prevent the deck of the ship from being soiled by the fuel oil which issues from the ventilation nozzle, hitherto recourse was made to the use of open collectors disposed beneath the outlet orifices of this nozzle.

In order to prevent all overflow fuel oil through the ventilation nozzle, in the ventilation tube carrying this nozzle it was possible to place an indicator of the presence of fuel oil, actuated by the rise of the fuel oil.

Such an arrangement however was not suitable for the service conditions which normally occurred in the filling of the tank, since the lapse of time between the actuation of the indicator and the overflow of the liquid was generally much too short for the pump to be stopped in time to prevent the overflow. It is true that in theory it would have been possible automatically to stop the flow as a result of the presence of the liquid in the ventilation tube, but such a device would most often have been too complicated and uncertain by reason of the conditions in which it operated, so that in practice it would be preferred regularly to look for the presence of fuel oil at the ventilation nozzle in conjunction with the use of collectors disposed beneath the nozzle.

This is why the invention has the purpose of supplying a device which in a simple and sure manner avoids the risk of pollution due to overflow of the liquid from the tank through its ventilation nozzle.

For this purpose a time interval should be available, between the observation of the level of the liquid in the ventilation nozzle and the overflow of the liquid from the ventilation tube, sufficient to permit the stopping of the pump in due time even in the case of only periodical inspection.

The present invention provides a cargo ship having a tank ventilation device of the type comprising a ventilation nozzle connected to a ventilation tube, in which said ventilation tube communicates through an overflow channel with a collecting enclosure for liquid which overflows from the tank and through the ventilation tube, said collecting enclosure being arranged beneath the upper deck of the ship, and said overflow channel extending between the ventilation nozzle and the upper deck of the ship. By suitably dimensioning this collecting enclosure the object is easily achieved of having sufficient time available, after observation of the overflow to give a signal for stopping of the pump, without the necessity for extra work in emptying collectors for liquid which has overflowed.

To this end the collecting enclosure is advantageously formed in the form of an overflow vessel which can be connected to the discharge conduit of the tank, so that both the liquid that has overflowed and the liquid normally contained in the tank can be discharged with the aid of pipelines provided to deliver the liquid to the point of use. For this purpose the collecting enclosure can be connected with the tank of the ship through an outlet conduit in which a nonreturn valve is provided for closing the conduit in the return direction and opening the conduit in the direction of discharge. In this way an automatic transference of the collecting enclosure from its collecting function to a function of discharge to the location at which the fuel oil is required is obtained.

Advantageously a ventilation nozzle is provided which is protected against any pollution by overflow, in that both the ventilation tube and the collecting enclosure are in communication in parallel with the ventilation nozzle. In this way, in spite of the communication of the enclosure with open air through the nozzle, the object is achieved that it is possible to dispense with any open collecting vessels.

A particularly simple form of the ventilating device which is of low bulk is obtained by providing for the collecting enclosure a tubular column supporting the ventilation nozzle, surrounding the upper part of the ventilation tube. This annular enclosure thus defined between this column and the upper end of the tube can be arranged to open into a collecting chamber disposed beneath the deck of the ship.

It is easily possible to provide sufficiently large dimensions for the liquid collecting enclosure to avoid with certainty any escape of the liquid from the ventilation nozzle, by casual inspection of the state of any overflow, the inspection being for example through an observation aperture disposed in the nozzle. If it is desired to prevent escape of the fuel oil from this ventilation nozzle and the consequent pollution even in the case where there is no inspection of the amount of overflow, the collecting enclosure can be connected or made connectable by a return conduit to the admission side of the pump for charging the tank, so that the overflowing liquid is taken up by a circuit returning to this pump and thus any rise of the level of the liquid beyond the overflow level provided for the ventilation device is prevented.

The invention further offers the advantageous possibility that an overflow indicator, which can be connected to an alarm device or to a device for automatically stopping the charging pump, can be disposed in an easily accessible position which is suitable particularly both for assembly and for maintenance, namely in the collecting enclosure.

Further characteristics and advantages of the invention will appear from the following description, with preference to the non-limitative example shown in the accompanying drawings wherein: Figure 1 represents a vertical sectional view of a first form of ventilating device in accordance with the invention, taken along the line I-I in Figure 2; Figure 2 is a partial side view of the device of Figure 1; Figure 3 is a vertical sectional view of a second form of ventilating device in accordance with the invention, taken along the line llIIII in Figure 4; and Figure 4 is a side view thereof, taken in- section in its upper part along the line IV-IV in Figure 3.

These two forms show the application of the device under consideration to two different types of ventilation nozzle.

These nozzles 2 or 2a serve for the ventilation of a ship's tank through a ventilation tube 1, which extends from this tank, normally disposed above the bottom B of the ship, to above the upper deck 15 thereof and projecting therefrom.

The nozzle comprises a connection chamber 3 or 3a which is directly connected to the exit end of the tube 1 and communicates with the open air through intermediate chambers 4 or 4a and open exit chambers 5 or Sa. These exit chambers communicate with the open air through ventilation orifices 6 or 6a and in the usual way, in order to avoid admission of water, they are equipped with non-return valves 7 or 7a which comprise hollow spherical closure members which, on entry of water, are applied to valve seatings constituted by apertures 7b communicating with the intermediate chamber 4 or 4a. In the example of Figures 1 and 2 grids 8 are provided on ventilation orifices 6 which prevent the closure members from dropping out and foreign bodies from penetrating. In this example also the exit chambers and the intermediate chambers are constituted by shaped elements which can be fixed on the connection chamber 3 by flanges 9 equipped with fireproof wire gauzes 10, while in the second example of Figures 3 and 4 the connection chamber 3a coaxially surrounds a single exit chamber 5a and includes a part constituting the intermediate chamber 4a situated above this exit chamber.

The latter communicates with the open air through fireproof wire gauzes 10 and open boxes fixed with the aid of flanges.

At the lower part of the connection chamber 3 or 3a there is provided a tubular support 11 which is fixed by means of a flange 12 on a support column 13 which is fixed by a base flange 14 permanently, as by welding, on the deck 15 of the ship.

The part of the ventilation tube 1 which projects above the deck 15 is surrounded coaxially by the tubular support 11 and the support column 13, with a spacing which defines a free annular chamber 17. The upper extremity of the tube 1 thus constitutes a free overflow edge 16 for the liquid from the tank which rises in the tube 1 and, as represented by the arrows in Figure 1, then drops back into the annular chamber 17. The latter communicates through a deck opening 19 with a collecting chamber 18 or 1 8a situated beneath the deck. In order to form this chamber it is possible to use the existing transverse partitions 20 beneath the deck in the vicinity of the tube 1 which are completed, so as to constitute a closed com partment, but suitable lateral partitions connecting them and by a bottom 21, also by the part of the deck situated between these lateral walls. This collecting chamber 18 communicates with the ventilation tube 1 through an aperture 22 formed in its bottom and an outlet conduit 23, so that after the pump charging the tank has been stopped and when the discharge of the liquid to the point where it is required takes place, it is possible to return into the tank (discharge direction A) the liquid F which has overflowed and collected in this chamber 18.

The liquid then passes through the discharge conduit of the tank. Direct return (direction U) of the liquid to the chamber 18 through the conduit 23 is prevented by a non-return valve 24 having a spherical closure member and a valve seating.

The collecting enclosure formed by the annular enclosure 17 and the collecting chamber 18 is dimensioned so that it always accommodates the oil that may escape during the time interval elapsing until the stopping of the charging pump, it being assumed that there is suitable inspection of the state of overflow above the edge 16 of the tube, through an observation aperture 25 in the wall of the connection chamber 3, that is to say in such manner as to prevent the liquid from rising in the connection chamber and flowing through the intermediate chamber 4 and the exit chambers 5.

In the example of Figures 3 and 4 the collecting enclosure 17, 18a is connected or arranged to be connected to the suction side of the pump for charging the tank through a connection pipe 26 and through a return conduit. The liquid which overflows over the edge 16 therefore returns continuously to the charging pump, so that this overflow can never result in liquid flowing outside the ventilation nozzle.

It is apparent that without departing from the scope of the invention, various modifications can be made to the devices which have been described. Thus in particular the collecting enclosure can be supplementarily equipped with an overflow indicator 27 which can actuate an optical or acoustic alarm device or a device for the automatic stopping of the charging pump.

WHAT WE CLAIM IS: 1. A cargo ship having a tank ventilating device of the type comprising a ventilation nozzle connected to a ventilation tube, in which said ventilation tube communicates through an overflow channel with a collecting enclosure for liquid which overflows from the tank and through the ventilation tube, said collecting enclosure being arranged beneath the upper deck of the ship, and said overflow channel extending between the ventilation nozzle and the upper deck of the ship.

2. A cargo ship according to Claim 1, in which the collecting enclosure communicates with the tank through an outlet conduit in which a non-return valve is located for closing the outlet conduit against return of the liquid to the enclosure but permits flow through the outlet conduit to the tank.

3. A cargo ship according to either of Claims 1 or 2, in which the ventilation tube and the collecting enclosure communicate with the ventilation nozzle in parallel.

4. A cargo ship according to any of the preceding claims, in which the collecting enclosure or overflow channel is formed in part by a support column for the ventilation nozzle which surrounds an outlet end portion of the ventilation tube thus forming an annular enclosure surrounding the ventilation tube.

5. A cargo ship according to Claim 2, in which said support tube communicates with an opening of the upper deck and the ventilating tube passes through this opening through the ship's deck and extends through the bottom of the collecting chamber.

6. A cargo ship according to any of the preceding claims, in which the collecting chamber is bounded on opposite sides by transverse partitions in the ship on either side of the ventilation tube.

7. A cargo ship according to any of the preceding claims, in which the outlet conduit of the collecting enclosure communicates with the tank through the ventilation tube.

8. A cargo ship according to any of the preceding claims, in which an observation aperture is provided in the ventilation nozzle for the inspection of any overflow.

9. A cargo ship according to any of the preceding claims, in which the collecting enclosure is equipped with an overflow indicator.

10. A cargo ship according to any of the preceding claims, in which the collecting enclosure is connected or arranged to be connected through a return conduit with the suction side of a charging pump for the tank.

11. A cargo ship according to any of the preceding claims, in which the collecting enclosure is large enough to contain at least the amount of tank liquid delivered by the filling pump after cutting off following observation of overflow beneath the ventilation nozzle.

12. A cargo ship having a tank ventilation device substantially as hereinbefore

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. partment, but suitable lateral partitions connecting them and by a bottom 21, also by the part of the deck situated between these lateral walls. This collecting chamber 18 communicates with the ventilation tube 1 through an aperture 22 formed in its bottom and an outlet conduit 23, so that after the pump charging the tank has been stopped and when the discharge of the liquid to the point where it is required takes place, it is possible to return into the tank (discharge direction A) the liquid F which has overflowed and collected in this chamber 18. The liquid then passes through the discharge conduit of the tank. Direct return (direction U) of the liquid to the chamber 18 through the conduit 23 is prevented by a non-return valve 24 having a spherical closure member and a valve seating. The collecting enclosure formed by the annular enclosure 17 and the collecting chamber 18 is dimensioned so that it always accommodates the oil that may escape during the time interval elapsing until the stopping of the charging pump, it being assumed that there is suitable inspection of the state of overflow above the edge 16 of the tube, through an observation aperture 25 in the wall of the connection chamber 3, that is to say in such manner as to prevent the liquid from rising in the connection chamber and flowing through the intermediate chamber 4 and the exit chambers 5. In the example of Figures 3 and 4 the collecting enclosure 17, 18a is connected or arranged to be connected to the suction side of the pump for charging the tank through a connection pipe 26 and through a return conduit. The liquid which overflows over the edge 16 therefore returns continuously to the charging pump, so that this overflow can never result in liquid flowing outside the ventilation nozzle. It is apparent that without departing from the scope of the invention, various modifications can be made to the devices which have been described. Thus in particular the collecting enclosure can be supplementarily equipped with an overflow indicator 27 which can actuate an optical or acoustic alarm device or a device for the automatic stopping of the charging pump. WHAT WE CLAIM IS:

1. A cargo ship having a tank ventilating device of the type comprising a ventilation nozzle connected to a ventilation tube, in which said ventilation tube communicates through an overflow channel with a collecting enclosure for liquid which overflows from the tank and through the ventilation tube, said collecting enclosure being arranged beneath the upper deck of the ship, and said overflow channel extending between the ventilation nozzle and the upper deck of the ship.

12. A cargo ship having a tank ventilation device substantially as hereinbefore

described with reference to Figures 1 and 2 of the accompanying drawings.

13. A cargo ship having a tank ventilation device substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.