The present invention refers to a collar, in the form of a trough, which is applied to the upper external rim of a fuel reservoir resulting in an annular water reservoir which circumscribes the whole diameter of the. fuel reservoir.

In case of fires in fuel reservoirs, the highest temperatures are found in the plates forming the upper rims of the reservoirs since it is there that the evaporated fuel feeds the fire upon contacting the oxygen in ^■ he air. The heat produced raises the fuel temperature beyond the boiling point. There is also the overheating of the ri - -forming plates which results in a reduction in their resistence, to the extent that they fold one on top of the other, so that the whole reservoir is destroyed.

The main use of the trough-like collar of the present invention is, in case of fire in the fuel reservoir, to maintain the. upper reservoir plate in direct contact with the cold water stored therein, thus avoiding higher temperature elevations.

Another useful application of the present invention is in the daily handling of fuel into the reservoir. Since the fuel to be stored in the reservoir most of- the times arrives in a hot state, a ready cooling thereof caused by the water in the trough diminishes the fuel losses resulting from evaporation. The invention is also useful for cooling products of a toxic content which are stored in reservoirs, thus avoiding the risk of accidents caused by overheating of said products.-

The trough-like collar of the present invention may have perforations or serriform grooves in the upper section thereof to allow the excess water flow downward on the external reservoir walls which results- in uniform cooling of the reservoir contents and better utilization of the water used. The water used may be partiall recovered if another trough is adapted around the reservoir next to its base.

In the accompanying drawings, Figure shows a fuel reservoir to which a trough-like collar has been applied. In order to clarify the operation of the invention, the parts which form it are indicated by reference numerals: 1-fuel reservoir; 2-trough-like collar; 3-serriform grooves in the upper rim of the trough-like collar; 4-overflow holes on the trough-like collar; 5-inlet tube for the water; 6-upward rising tube; 7-water distribution pipe; 8-feeding terminal between the resei-Voir wall and the trough-like colla 9-water-jet; 10-water stored between the trough-like collar and the reservoir wall; 11-upper reservoir rim.

Figure 2 shows in detail the trough- -like collar 2 full of water 10, being fed by a water jet 9 which sprays water from both sides of the upper end of distribution pipe 7. A uni orm volume of water must be flowing through serriform grooves 3 and overflow holes 4 in order to maintain the reservoir external walls completely wet.

The upper rim 11 of the reservoir stands higher than the serriform edge of the trough 2, and the difference in height between the two must be only enough to encompass the eddying effect and the height of the waves produced by force feeding the water.

In a variant of the present invention, it may be a walkway disposed around the top of a fuel reservo and serving also as a reinforcement therefor, said walkway being inclined outwardly and storing a certain -amount of wate and in order to be less slippery it is perforated all around allow drainage of rain water; in case of fires, it can be

filled in by the firemen's hoses so that the same effect of the trough-like collar is produced.