RU2707768C1 - Method of applying polyurethane coating on fuel tanks - Google Patents

Abstract

FIELD: motor vehicle industry.

SUBSTANCE: invention relates to methods of producing a solid polyurethane shell on the surface of metal tanks and can be used in transport engineering, where there is need to protect fuel tanks. In the method of applying a polyurethane coating on a fuel tank, it is placed in a mold at a certain distance from the walls, defined by the shape and size of beacons. Liquid polyurethane under pressure is supplied from below. Air from the cavity is forced out through the highest point of the mold.

EFFECT: possibility of obtaining a homogeneous structure and elasticity of the obtained polyurethane layer, a high-quality polyurethane layer on the curvilinear mating surfaces of the tank and the required thickness of the polyurethane layer, which provides reliable tightening of the holes during damage by bullets.

1 cl, 1 dwg

Description

The invention relates to methods for producing a continuous polyurethane shell on the surface of metal fuel tanks. The invention can be used in transport engineering, where there is a need to protect fuel tanks.

The method consists in placing the fuel tank in a mold consisting of sections connected by bolts. The form, together with the tank, is mounted on a stand at a certain angle. From below, under pressure of 1-2 kgf / cm ² , liquid polyurethane is supplied, which, rising, fills the cavity between the tank and the mold, and the air is forced out through an opening located at the top point of the mold. After polymerization, a monolithic, uniform layer of polyurethane of the required thickness is created on the surface of the tank.

Close in technical essence to the present invention is a method of bonding a polyurethane coating with a metal surface, by pre-layer-by-layer coating of the adhesive composition in the form of a solution in an organic solvent of a mixture of a polyester, diisocyanate and a curing catalyst and subsequent curing. [1 - patent No. 994528]. The disadvantages of this method;

1. The great complexity of creating such a coating.

2. The presence of joints between glued polyurethane plates.

The presence of joints reduces the strength of the shell. In addition, the polyurethane layer is heterogeneous in structure. These circumstances can cause premature destruction of the shell along the joints.

3. Difficulties in bonding the plates at the transitions between the curved mating surfaces of the tank.

The prototype of the claimed invention is the invention "Fuel tank and method for its manufacture" [2 - patent No. 2090382].

According to the invention, the fuel tank contains an open-cell elastic polyurethane foam filler and a dense polyurethane sheath made by spraying. For ease of installation of the tank in the machine, the shell will be flexible and not adhered to the surface of the filler. The shell is mounted in the machine separately from the filler, after which the inner space of the tank is filled with filler, which, together with the shell, provides fire safety of the tank.

The disadvantages of the method:

1. For effective tank protection, a layer of polyurethane with a thickness of at least 6-8 mm is required. (This thickness ensures the restoration of the resulting hole from the bullet).

The thickness of the polyurethane layer with a single spraying or brushing is approximately 0.2 mm. Therefore, to obtain a polyurethane layer of the required thickness, repeated repetition of spraying or brushing is required, with the obligatory polymerization of each applied layer. Therefore, this method is laborious and uneconomical.

2. In the curved mating surfaces of the tanks, an inhomogeneous layer of polyurethane with an unequal thickness is obtained.

3. It is difficult to obtain uniform thickness on the entire surface of the tank.

In addition to filling the tanks with open-cell PPU-EO-100 polyurethane foam, an external polymer coating of the tanks (PUM-PF-OP-15 polyurethane) is used. This material has the property of self-tightening holes, which prevents leakage of fuel and its ignition [3 - Fire and explosion-proof fuel tanks and explosion-proof gas cylinders.]. Here are the data on the testing of tanks with a continuous polyurethane layer on the surface, obtained by a machine method, but not given data on:

- How is the tank installed relative to the inner surface of the mold? (This achieves the thickness and quality of the resulting polyurethane layer).

- The geometric arrangement of the form in space.

- The method of supplying liquid polyurethane.

- The quality of the resulting layer.

- Ability to extract the finished product from the mold, etc.

Our proposed method allows to achieve a technical result, namely;

- homogeneous structure (absence of pores and air bubbles) and elasticity of the resulting polyurethane layer;

- a high-quality polyurethane layer on the curved mating surfaces of the tank;

- high-quality adhesion of the polyurethane layer and the metal surface of the tank;

- the required thickness of the polyurethane layer, which provides reliable tightening of the holes when hit by bullets.

The inventive method is as follows:

Polyurethane plates of the same thickness, the so-called “beacons”, are glued onto the tank all over the circuit at a certain distance (this ensures a uniform gap between the tank and the mold, and, as a result, the same thickness of the future polyurethane layer).

The tank is placed in a mold consisting of sections interconnected by bolts. This makes it possible then to disassemble and remove the finished product without damaging the polyurethane layer.

Liquid polyurethane in the form is supplied from below under a pressure of 1-2 kgf / cm ² . Polyurethane rises slowly and gradually displaces air from the cavity between the mold and the tank. This ensures a uniform and dense layer of polyurethane. After full filling with polyurethane, the mold with the tank will be placed in a furnace where polymerization takes place in accordance with the technology of the polyurethane used. Then the tank is taken out of the furnace and polymerization of the polyurethane at room temperature continues. At the end of the polymerization, the mold is disassembled and the tank is removed from the mold.

In FIG. 1 shows a form with a fuel tank installed in it.

The proposed method is as follows.

Polyurethane plates of the same thickness, the so-called "beacons" pos. 2 (this ensures a uniform gap between the tank and the mold, and as a result, the same thickness of the future polyurethane layer).

The tank is placed in the form of poses. 3, consisting of sections interconnected by bolts. From below into the tank by the pipe pos. 4 under pressure of 1-2 kgf / cm ² liquid polyurethane is supplied, which, rising, displaces the air between the tank and the mold. Air through the tube pos. 5, located at the top of the mold, is displaced into the atmosphere. When the mold is completely filled, the flow of polyurethane is stopped.

The mold, together with the tank, is placed in a furnace heated to the required temperature. Under the influence of temperature, the necessary structural changes occur in polyurethane. After a certain time, the mold is removed from the furnace. After cooling, the mold is taken apart and a tank with a polyurethane layer applied.

Thus, the proposed method allows to obtain an elastic layer of polyurethane with the required thickness and uniform structure. The method allows you to get a uniform layer of polyurethane on the entire surface of the tank.

METHOD FOR APPLYING POLYURETHANE COATING TO FUEL TANK

Information sources:

1. Patent 994528. A method for bonding a polyurethane coating to a metal surface. Design and technological bureau of chemical engineering of the Ministry of chemical and petroleum engineering of the USSR. Authors V.A. Voroshilov, E.V. Gerlivanov, V.A. Gromov et al. Publ. 03/27/1983

2. Patent No. 2090382. Fuel tank and method of its manufacture. Joint-Stock Company "All-Russian Scientific Research Institute of Transport Engineering". Authors V.M. Bakshinov, V.K. Borzov, S.B. Malin et al. Publ. September 20, 2007

3. Fire and explosion-proof fuel tanks and explosion-proof gas cylinders of NII Steel OJSC. Information Agency "Arms of Russia". 08/29/2012

Internet www.arms-expo.ru.

Claims (1)

A method of applying a polyurethane coating to a fuel tank, characterized in that in order to obtain a continuous homogeneous polyurethane layer on the entire surface, the tank is placed in a mold at a certain distance from the walls, determined by the shape and size of the “beacons”, liquid polyurethane is supplied from below under pressure, and air from cavity is displaced through the highest point of the mold, polyurethane flows around the tank from all sides, creating a continuous uniform layer.

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