Quality Assurance

ISO Certification

ISO Certification until September 2007
Currently in the confirmation process.

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SQAIR – Shell Quality And Inspection Requirements

Specification for liner and screens in the area of crude oil and natural gas by con-slot

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Mechanical Properties

Strength by all-welded structure:

Since we work exclusively on the concept of profile wire screens these are elaborated upon by using up-to-date and modern manufacturing methods, such as a resistance welding method developed by us only for us. The screen structure is a combination of surface profiles and supporting profiles, fusion-welded under water at each crossing. Carefully selected parameter guarantee that the material structure of the screen welded members remains practically unchanged. Fusion welding and the correct selection of profile combination prevent stress cracks or even detaching of surface profiles from their supports.

Also welding procedures used in the process of fitting the well screens and -pipes with the connectors and armatures, etc. necessary for easy installation, are carefully chosen with the same attention which we ourselves claim for our products. Only the most modern welding - and cutting procedures according to DIN 1910 like TIG, MIG, PLASMA and LASER are employed for the manufacturing of con-slot products.

The continuity of the con-slot quality level is assured by our skilled employees, certified and controlled by the German TÜV, and also by our company's internal and independent quality control our quality manual being the structural guideline.

Qualität 1

Qualität 2

Photos of micro-cut,
performed by TÜV Hanover 500:1 and 1000:1
proving the homogenous granular structure in the welding zone.

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Collapse strength – burst strength – buckling strength – column strength

Research conducted as mass tests on con-slot screens have proven, the screen structure is comparable with thin-walled or thick-walled cylinders. However, the definite condition for this behaviour is a fusion-weld between the surface profile and the supporting profile at each crossing. A comparison of the test results of collapse pressure and burst pressure with the theoretical results from different formulas like

indicate clearly that the results coming from the formulas of AD-Merkblatt differ the least. Therefore we strongly recommend the use of the AD-Merkblatt-formulas.

The equivalent wall thickness of a screen is achieved by calculating the moment of inertia of the screen structure. Then this equivalent wall thickness is introduced into the next step of stress calculation.

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Bending moments

Ideal combination of surface profiles with supporting profiles having high moments of inertia results in high bending stresses of screens together with incomparable high permeabilities. The advantage can be found in the economic and efficient design of con-slot high efficiency well screens.

Deformation due to overloading a con-slot screen has shown that due to the high quality fusion welding the screen structure will not be destroyed. The screen functioning is not interrupted, even though with a reduced capacity and higher pressure loss, the operational safety remains because no parts from the screen body are loosened and separated and consequently cannot cause damage to other operational installations like submersible pumps, etc.

To manufacture a well screen only based on strength requirements is relatively simple. However, to combine such strength with incomparable free entrance area and extraordinary hydraulic properties needs more skill. con-slot high efficiency well screens combine these requirements in know-how and economy.

Qualtät 3 Qualtät 4


Qualität 5


Typical deformation of a screen body due to excessive differential pressure

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con-slot SCREENS | Industriegebiet Hafen | Graue Riethe 2 | D-29378 Wittingen
Tel: +49 5831 2515-0 | Mail: info@con-slot.de