WHAT IS A FLANGE?

Flange is an item that connects two components of a piping system, which enables its dismantling by non destructive operations, thanks to a circle with holes where the union bolts are matched.

WHAT IS A PRESSED FLANGE?

The Pressed Flange Fittexport (we will also call it FITT Flange) is the improvement not only in design and functionality but also in price of the traditional Back-Up Flange (we will also call it “solid flange” or “plate flange”).

We know the loose flange (Back-Up) made from forging.

Thanks to the forming of plate we can get the Pressed Flange Fittexport.

It is the same product and offers the same technical performance in less weight and less price.

THE QUALITY OF THE PRESSED FLANGE

Fittexport wants to communicate the high quality level of the Pressed Flange Fittexport and for that purpose it has been made a study of the behaviour of the pressed flanges, in cooperation with the Engineering Faculty of the Barcelona University, the Ascamm Foundation and Applus.

The purpose of this study was to check the performance of the Pressed Flange Fittexport and observe its resistence and stiffness features.

The flange was subjected to a static structural analyse carried out with the most advanced analyses programs.

THE QUALITY OF THE PRESSED FLANGE - the test

This test consists of applying the nominal pressure 10bar (PN10) on the outside part of the flange, observing the behaviour of the piece in the most stressed possible situation and see if the pressed flange can work at the same level as the plate flanges in the tensions that they have been designed for. The inner part of the piece suffers a deformation of 3micra, which is definitely imperceptible.

We can observe on the tension diagram that the maximum superficial tension that the piece suffers in one point is 9,5MPa and the elasticity limit of the piece is 200MPa.

THE QUALITY OF THE PRESSED FLANGE - the result

The maximum tension value is located on the contact surface of the pressed flange with the bolt and it is 28MPa, what represents the 9% of the yield stress of the steel 1.4404 and 1.4307. The deformations are negligible.

The Pressed Flanges Fittexport react satisfactorily to the imposed pressure.

We confirm that the Pressed Flange Fittexport is able to endure the pressure test internally and externally, with the same results as the solid flange.

WHY A PRESSED FLANGE IS BETTER THAN A SOLID FLANGE?

• A pressed flange is 61% lighter than a solid flange, which means also a noticeable reduction of the price.
• The pressed flange is cheaper than the solid flange.
• Thanks to its lightness, the pressed flange is easier to install than the solid flange.
• The morphology of the pressed flange increases the water-tightness inside the system, because it has a flap in the interior diameter in contact with the collar, which exerts a pressure on the collar higher than the one exerted by a solid flange.
• Apart from that, the pressed flange behaves as a solid flange.

WHY THE FITT FLANGE IS MADE FROM STAINLESS STEEL?

In the chemical and petrochemical industry, the stainless steel offers a high resistance to corrosion and excellent mechanical characteristics. The main advantatges of stainless steel are:

• High resistance to corrosion.
• High mechanic resistance.
• Hygienic appearance and properties.
• Resistance to high and low temperatures.
• Good properties for welding, mechanizing, cutting, bending and folding.
• Low maintenance cost.
• Recyclable.

As a result of the combination of added elements like nickel, chrome, molibdenium, titanium and others, today there are different types of stainless steel with inherent properties suitable for different uses.

FINISHING OF THE FITT FLANGE: SHOT BLASTING

The steel blasting is a technique for surface treatments made by impact, and consists in shooting the surface with thousands of small steel balls at a speed of 65 to 110 m/sec. The cinetic energy released from the impact of the balls against the piece causes that the external surface of the steel balls break and sticks on the piece forming a soft roughness on the surface.

Advantages of shotblasting:

• Allows to get an excellent degree of cleanliness and a correct finishing of the surface.
• Increases the resistance of the materials to the wearing out so it reduces the risk of fractures.
• The process does not generate heat that modifies the structure of the materials.
• The roughness on the surface is more perceptible than in a chemical pickling so it helps to the adherence of later coatings (painting, rubber, etc.).

FINISHING OF THE FITT FLANGE: PICKLING

It is a chemical treatment used to eliminate imperfections, pollutants and stains on the material.

The finishing that we get from this process is a smooth, clean and passivated surface with anti-corrosion protection and matt or glossy appearance.

SETTING UP OF THE FITT FLANGE

The setting up of a FITT Flange is as simple as the setting up of a solid flange. The set is made up of two collars, two flanges, one joint and several bolts (the number of bolts is different according to the size of the flange). The localization of the maximum stress according to the Von Mises Analyses suggests the use of washers on the assembly of the bolts.

Firstly the flanges are placed between the tubes and the collars, then the collars have to be welded to the tube, a joint is placed between the collars and finally the bolts and washers are assembled.

Fittexport produces all kind of collars suitable for the pressed flange.

APPLICATIONS

The Pressed Flange Fittexport can present different finishings according to its final use: shotblasted, pickled, polished, and it is used in the following sectors:

• Offshore platforms & shipyard industry
• Chemical & pharmaceutical industry
• Pulp & Paper industry
• Water treatment
• Food & Beverage industry
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