CS276786B6 - The wall of the tank for flammable liquids with protection against dangerous effects of static electricity - Google Patents

Abstract

The wall of the tank for flammable liquids with protection against the dangerous effects of static electricity in double-walled tanks with an inner plastic bag allows their use for flammable liquids of I. and II. hazard classes and eliminates the violation of the monitored vacuum. It reduces the costs of protective systems for flammable liquids of I. and II. hazard classes. These shortcomings are eliminated by the wall of the tank for flammable liquids with protection against the dangerous effects of static electricity by placing a lining between the outer wall and the wall of the plastic bag. The lining is made of a lining mat on which a conductive electrode is placed.

Description

The invention relates to the walls of a tank for flammable liquids with protection against dangerous effects.

static electricity for double-shell tanks with an inner plastic bag.

As one of the very effective protections of surface and groundwater against pollution by oil and oil products, a system of double-walled storage tanks is currently used. It is a preventive protection, based on the creation and monitoring of a small vacuum in the space between the inner and outer shell of the protected tank. A leak in a casing represents a violation of the monitored vacuum and the subsequent signaling of this condition. With a high economic effect, it is used to make the inner shell of plastics chemically resistant to petroleum products. In practice, a lining mat, for example a porous material with a thickness of about 10 mm, is glued or otherwise fastened to the inner walls of the tank, which on the one hand forms a space for creating a vacuum and on the other hand suitably adjusts mechanical properties, i.e. covers sharp edges of the tank wall. A plastic bag of the same dimensions as the tank is mounted in the tank prepared in this way. By creating a vacuum in the space formed by the lining mat between the plastic bag and the tank shell, it is achieved that the inner plastic bag fits perfectly on the lining mat mounted on the walls of the tank. However, from the point of view of protection against the dangerous effects of static electricity, the solution with a plastic inner jacket can generally only be used for combustibles III. ' and IV. hazard class, ie for flammable liquids whose vapors do not form an explosive mixture with air at normal temperatures. In practice, these are mostly diesel and oils. This is because the plastic protective bag is made of an electrizable material and thus does not dissipate electric charges from the stored flammable liquid, the vapors of which form an explosive mixture with air at normal temperature and, in addition, generate an electric charge on their surface. In general, these are liquids I. and II. hazard classes such as petrol and kerosene. The use of plastic bags made of electrostatically conductive material would solve this problem, but unfortunately such material is not yet available.

The above-mentioned drawbacks are eliminated by the wall of the tank for flammable liquids according to the invention, the essence of which consists in that a lining is placed between the outer wall and the wall of the plastic bag. The lining consists of a lining mat on which a conductive electrode is placed.

Due to the fact that for flammable liquids I. and II. In hazardous classes, it is necessary to use very expensive protection systems, ie, for example, double-skinned metal tanks and tanks realized in holding tanks, the proposed solution is highly economical. The effectiveness of this solution is even more pronounced if we realize that it is possible to modify existing above-ground and underground reservoirs without demands on construction activities.

The essence of the proposed solution lies in the fact that in the whole space between the inner plastic bag and the lining mat an electrically conductive grounded layer or network would be created, which would bind the electric charges in the flammable liquid capacitively or inductively and thus no electrostatic discharge could occur. could subsequently initiate an explosive mixture accumulated over the flammable liquid. A conductive lining mat can also serve as an electrode.

The attached figure schematically shows an exemplary embodiment of a flammable liquid tank wall according to the invention, in which Fig. 1 is a general embodiment of a wall with a conductive lining and Fig. 2 is an embodiment of a wall with a lining mat and a grounded conductive electrode.

Example 1

The lining £ is formed by a lining mat which is electrostatically conductive in its entire volume. A plastic bag £ is then mounted on it in the usual manner.

Example 2

A conductive electrode, for example a perforated conductive foil, is glued, sewn or otherwise attached to the lining mat 6. The lining mat 6 thus prepared is inserted into the tank by a conductive electrode £ inside the tank, the conductive electrode £ being grounded by a connection to the wall £ of the protected tank. A plastic bag 1 is then mounted on this conductive and grounded electrode 6.

CS 276 786 86

Example 3

The plastic bag 2 is provided on the outside with a conductive electrode 2, for example by conductive coating, paint or by gluing a conductive foil. The plastic bag 2 thus treated is mounted on a conventional untreated liner 2 in a tank and the conductive electrode 2 of the plastic bag 2 is grounded to the wall 4 of the tank.

Claims (2)

PATENT CLAIMS A wall for a tank for flammable liquids with protection against the dangerous effects of static electricity for double-walled tanks with an inner plastic bag, characterized in that a liner (2) is arranged between the outer wall (4) and the wall of the plastic bag (1). 2. The wall of a tank for flammable liquids with protection against the dangerous effects of static electricity according to claim 1, characterized in that the liner (2) is formed by a liner mat (5) on which a conductive electrode (3) is placed.