ES2540938B1 - Procedure for the application of GRP layers with vacuum technique in liquid storage tanks - Google Patents

Abstract

Procedure for the application of GRP layers with vacuum technique in liquid storage tanks where, once the bag (5) has been introduced into the tank (1) and prior to the vacuum process to form the GRP layer, it includes the introduction of air inside the bag (5), causing it to behave like a balloon to adapt to the inner walls of the tank (1) overcoming the forces of gravity. Preferably, in addition, it contemplates the use of an inflation valve (6) which is incorporated coupled to the mouth of the bag and coincides with the mouth (2) of the tank and which can be removable. For the introduction of air into the bag, for example, an air compressor (8) is used.

Description

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PROCEDURE FOR THE APPLICATION OF GRP LAYERS WITH VACUUM TECHNIQUE IN LIQUID STORAGE TANKS

D E S C R I P C I O N

OBJECT OF THE INVENTION

The invention, as stated in the present specification, refers to a process for the application of layers of GRP ("fiber reinforced plastics") with watt technique in storage tanks of Kquidos, which provides, to the function to which it is intended, several advantages and novelty characteristics that will be described in detail below and that represent an improvement against the systems currently known in the state of the art for the same purpose.

More particularly, the object of the invention focuses on a process that aims to facilitate the application of the layers of reinforcement or creation of double interior walls with ford techniques in liquid storage tanks, particularly product storage tanks Petroleum Kquidos or any other type of liquids capable of contaminating the subsoil, whether new construction or for the repair and / or transformation of existing tanks, this process being aimed at overcoming the difficulties involved in the application of such layers with said technique, since it is an application inside the tank and, therefore, having to overcome the forces of gravity and the inconvenience of unique access from the mouth of the tank, for which it is essentially based on a previous application of air inside.

FIELD OF APPLICATION OF THE INVENTION

The field of application of the present invention focuses on the industry sector dedicated to the manufacture and / or repair of single or double wall tanks for the storage of liquid products, particularly focusing on those intended to contain potentially polluting liquids.

BACKGROUND OF THE INVENTION

As is known, the elaboration of fiberglass reinforced plastic composites

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GRP through the application of ford techniques, (VIP of the English vacuum infusion process) have been developed for more than 30 years for various industrial applications of large parts: airframes, wings and other parts of aviation; wind turbine blades; rail car housings / enclosures; boat hulls of all kinds; etc.

In a logical process of searching for product improvements, it has gone from the experience of manufacturing large parts, especially swimming pools, through the wet (manual) route to applications by VIP procedures because it is the simplest and safest operational route.

As a consequence we went from the construction of the large pieces in “open” molds by wet way to build these same pieces also in open molds but closing them with the ford bags for the VIP systems. The advantages obtained have been very relevant especially in the resulting products and in the conditions for the operators of improvement and reduction of emissions.

In view of the problems arising from working with the wet road in the repair and improvement of liquid oil product tanks (PPLs) such as unhealthy conditions for operators, indeterminate results and atmospheric emissions of styrene, the applicant himself has developed several procedures that apply the VIP technology to these tanks and that are registered in the following patents:

PCT / ES / 2011/070152, relating to a “Procedure to improve, repair and waterproof a steel tank that has lost its tightness as well as for its transformation into a double-walled tank”;

ES2412488A1, referred to a “Procedure to increase safety and detect leaks in liquid storage tanks and tank obtained”;

ES2430197A1, which discloses another "Procedure to transform an existing single wall tank into an intrinsically safe double wall tank".

The problem lies in the difficulties involved in executing the application of the ford or VIP technique inside the existing tanks.

Indeed, before proceeding to pass a single wall double wall tank

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by building a new wall inside it, it is necessary to repair it and, where appropriate, reinforce the original wall with a new GRP coating.

The VIP technique is a technology of closed molding of fiberglass reinforced plastic - GRP. The concept of this technique is to use the pressure of ford to push the liquid resin to the dry tissues that have been placed in a mold that is closed by the plastic bag.

It is therefore necessary a rigid and tight surface that acts as a mold and a flexible surface that adapts to the shape of the former. The rigid mold in the case at hand is the steel tank and the flexible one a ford bag that is sealed to the rigid mold by means of a tight seal. Any process that uses a lower atmospheric pressure to drive the resin into the mold cavity is VIP (infusion molding to the ford).

So far this operation has been carried out by wet way and the objective of the present invention is to develop a system that will apply the improvements that VIP technology undoubtedly brings in the tanks, where the ford bag should be introduced inside the tank , being the difficulty of its correct adaptation to the interior walls of the tank the essential problem to be solved and to which the procedure recommended here responds.

The storage tanks of existing potentially polluting liquids, mostly buried, deteriorate with the passage of time, even losing their tightness with the consequent damages caused by contamination of the subsoil, product losses, and / or water inflows that deteriorate the stored product.

In the presence of an unusual water content inside and after a tightness test with unsatisfactory or negative result, the first action that proceeds is the emptying and extraction of the product that it could contain and its eventual repair or replacement.

These actions, planned and detailed in the UNE 53991 IN standard, have been implemented through the wet application of the PRFV even though the latest version of this standard, published in December 2011, already provides for the possibility of making repairs by other means, when he says:

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UNE 53991 IN. Plastics Repair and interior lining of metallic tanks, for the storage of petroKferos Kquidos products, with reinforced plastics ... / ... This report covers any type of application systems for the repair with reinforced plastic materials of metallic tanks.

This rule, as is obvious, was conceived and drafted in order to unify criteria and establish minimum safety, performance and quality parameters for such repairs. Logically, these minimum parameters must be taken care of whatever the repair system we apply.

Patent ES2412488A1, Procedure to increase safety and detect leaks in liquid storage tanks and obtained tank, refers to this aspect, however, it not only seeks to solve the problems of tank sealing but also provide it with a control system future to ensure their behavior.

This last aspect is not expressly included in the European Regulation, so it may not be valid for regulatory purposes or it may take time to recognize it, therefore it is the objective of this invention to remedy these defects by extension and greater scope of the previous one.

EXPLANATION OF THE INVENTION

Specifically, what the invention recommends is a procedure for the application of GRP layers with a ford technique in liquid storage tanks whose purpose is to overcome the difficulties involved in the application of fiber layers with said technique based essentially on a previous application of air inside the ford bag.

The application of the VIP inside a tank must be carried out solving the following problems:

- First, the ford application must be carried out inside a closed tank (it is considered a confined space) and which is accessed exclusively by its man-made mouth.

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- Second, this tank must be watertight so that the ford application can be brought to a good end.

In a normal VIP application the mold is open, the tissues are placed and on them the distribution tubes of the ford and the resins. Then the bag is placed on both and the air is taken out from inside.

The same procedure applied inside the tank would give up any of its application due to the numerous problems to be solved:

The tissues and tubes must be held against the tank wall, which is solved by the use of adhesives;

It is necessary to hold the bag if it is made inside and if it is done outside and we introduce it through the mouth of a man inside it must be held and supported so that it is adopting the interior shape .... with risks for the operators who have of working on it.

The recommended procedure specifically contemplates the use of reverse air. Since what it is has is a practically closed mold, the tank that is going to be coated and, inside, a bag that allows to take out all the air between it and the own tank that makes mold, must be placed, the technique applied is to inflate the bag to make it behave like a balloon.

For this, a compressor or an air pump can be used that is connected to an inflation valve expressly provided for this purpose at the mouth of the bag and which coincides with the mouth of the tank. This valve may or may not be removed later to achieve airtight seal.

Next we will proceed to extract the air that is still between the bag and the walls of the tank with the ford pump, but once the forces of gravity that impeded its placement have been overcome, we can make the infusion without major problems.

In addition, because all the tanks have a similar, cylindrical-horizontal shape, and rounded shapes, the placement of the bag is easily done.

In short, looking for a new application to the VIP system by applying it to the tanks

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Existing, the described procedure provides a way that facilitates its execution extraordinarily and that is totally new for the experts of the sector, accustomed as they are to their work in open molds.

Another no less relevant aspect of the application of the recommended process refers to the manufacturing of new tanks.

For the storage of Kids in new tanks, whether to install air or buried, the following types of tanks are used:

Conventional steel tanks

Plastic tanks that, in turn, we can differentiate between:

Those of GRP, normally manufactured by wet way, and

Polyethylene, manufactured by roto-molding or injection-blow molding

The present invention therefore has its field of application both in existing tanks and in the manufacture of new tanks.

The manufacturing problems derived from the injection-blowing techniques that are specified in the impossibility of exceeding 5000 liters of capacity due to the inapplicability of the surface-volume law with the consequent increase in the necessary pressures for this, can be solved with the present procedure in a very reasonable way.

The described procedure for the application of GRP layers with ford technique in liquid storage tanks represents, therefore, an innovative structure of structural and constitutive characteristics unknown until now for the purpose to which it is intended, reasons that together with its practical utility , provide it with sufficient grounds to obtain the privilege of exclusivity that is requested.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being carried out and in order to help a better understanding of the features of the invention, this descriptive report is accompanied, as an integral part thereof, of a set of drawings, in which with character Illustrative and not limiting, the following has been represented:

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Figure number 1.- Shows a schematic view section, according to a vertical longitudinal section, of a tank subjected to the procedure for the application of GRP layers with ford technique object of the invention.

Figure number 2.- Shows a schematic sectional view of a portion of the tank wall subjected to the procedure, once the forging technique has been applied, the arrangement of the layers thereof being appreciated.

PREFERRED EMBODIMENT OF THE INVENTION

In view of the aforementioned figures, and in accordance with the numbering adopted, an example of a liquid storage tank (1) can be observed that is provided superiorly with a manhole (2) or access through the that, after introducing a fiberglass layer (3) that is incorporated glued to the inner surface of the wall (4) by means of glues, the bag (5) is introduced that allows the technique to be carried out of ford to insufflate the resin and press it against said fiberglass layer (3) transforming it into a layer of GRP or plastic reinforced with fiberglass.

As can be seen in Figure 1, according to the recommended procedure, the introduction of air (marked in the figure by arrows) is contemplated inside the said bag (3), which is made of a flexible material, to make that adapts completely to the internal surface of the wall (4) of the tank (1) in all its points and recesses, regardless of its shape, including the upper areas, overcoming the forces of gravity.

To facilitate said introduction of air into the bag (5), and that a pump or any other appropriate means can be carried out by means of an air compressor (8), preferably, an inflation valve (6) is incorporated in the mouth of the bag which, in turn, adapts to the edges of the mouth (2) of the tank so that, after such introduction, it can be sealed so as to cause the vacuum in the intermediate space (7) between the wall (4) of the tank with the fiberglass layer (3) and the bag (5), the result being, as shown in Figure 2, the complete adaptation of said bag (5) against the

wall (4) exerting pressure on the fiberglass layer (3) that will be transformed into a GRP layer by setting the insufflated resin in said ford injection process.

Describing sufficiently the nature of the present invention, as well as the way of putting it into practice, it is not considered necessary to make its explanation more extensive so that any expert in the field understands its scope and the advantages that derive from it, stating that, within its essentiality, may be carried out in other forms of realization that differ in detail from that indicated by way of example, and to which it will also achieve the protection that is required provided that it is not altered, changed or modified. Its fundamental principle.

Claims (4)

5 10 fifteen twenty 25 ES 2 540 938 A1 R E I V I N D I C A C I O N E S 1. - PROCEDURE FOR THE APPLICATION OF GRP LAYERS WITH VACUUM TECHNIQUE IN LIQUID STORAGE TANKS which, said application consisting of the incorporation of the fiberglass (3) on the surface of the interior tank wall (4) ( 1) and the utilization of a vacuum bag (5) for resin infusion, is characterized in that, once the bag (5) has been introduced inside the tank (1) and prior to the ford process to extract The air remaining between it and the wall (4) with the fiberglass (3) and blowing resin to form the GRP layer, includes the introduction of air inside the bag (5), causing it to behave as a balloon to adapt to the inner walls of the tank (1) overcoming the forces of gravity. 2. - PROCEDURE FOR THE APPLICATION OF GRP LAYERS WITH VACUUM TECHNIQUE IN LIQUID STORAGE TANKS, according to claim 1, characterized in that it contemplates the use of an inflation valve (6) which is incorporated coupled to the mouth of the bag and in coincidence with the mouth (2) of the tank. 3. - PROCEDURE FOR THE APPLICATION OF GRP LAYERS WITH VACUUM TECHNIQUE IN LIQUID STORAGE TANKS, according to claim 2, characterized in that the inflation valve (6) that is incorporated coupled to the mouth of the bag is removable. 4. - PROCEDURE FOR THE APPLICATION OF GRP LAYERS WITH VACUUM TECHNIQUE IN LIQUID STORAGE TANKS, according to any of claims 1-3, characterized in that an air compressor (8) is used for the introduction of air into the bag .