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New working method for sealing leakages

Introduction

MultiMetall has developed and applied for a patent a new method for a quick sealing of leakages at any place at liquid carrying metal pipes or containers. The working method is used at systems where liquids pour out under pressure. These could be liquids like water, oil or fuel.

Description

At the new working method a ceramic-steel reinforced structural part consisting of lead and copper is used together with a PolymerMetal. The layer thickness of the ceramic-steel coating is 0,05 mm. By applicating the PolymerMetal onto the structural part a quick sealing of leakages is possible even at high pressures and big rates of flow within short time (ca 15 min to 60 min).

The product technology contains the "Direct-MM-Bonding", this means the direct bonding of the PolymerMetals MM-metal oL-steelceramic and MM-metal UW on contaminated surfaces. The "Direct-MM-Bonding"-technology has been developed by MultiMetall many years before and it has been used at many other repairs.

The structural part is a perforated plate consisting of a lead alloy. This alloy can be practical fitted to nearly every geometry easily without any special energy, because at a cold deformation a high deformation capability is given. The fitted copper alloy resists high pressures after closing. The coating with ceramic-steel owns deformation capability, too, and furthermore increases the stability altogether.

The PolymerMetals MM-metal oL-steelceramic with the further developed Hardener red and the new developed MM-metal UW-L with Hardener UW-L were especially formulated to resist loads as pressure, bending-traction and torsion. Furthermore the excellent peel properties and the improved bonding behaviour are outstanding material properties of these PolymerMetals.

After the structural part has been fitted to the geometry of the leakage's surface, it is coated with the suitable PolymerMetal, then pressed onto the leakage and fixed for ca 2 to 3 minutes. Then an overlapping second coating with a brushable PolymerMetal using a brush is applied. Then depending on the size of the leakage after ca. 15 - 60 min the slot-shaped opening of the structural part is closed with a small pipe wrench and the slot afterwards secured with a further layer of PolymerMetal.

Tests

Tests were simulated with different leakage sizes and forms at different places of metallic pipes and containers. In addition to that it was sealed at various pressures between 6 bar to 10 bar. Water, machine oil, diesel and benzine have been tested. At a leakage size of ca diameter 4 mm at a pressure of 6 bar a penetration of water of ca 15 litres/minute was measured. Here the escaping jet of water reached a height up to 6 metres.

At the following tests it was not determined the strength of the closed slot. Instead it shall be investigated how good it is especially the bonding/combine of the whole structural part on the surface of the pipe or container. For this reason a structural part without slot is used. Furthermore it is refrained from letting any liquid pouring out during positioning the structural part onto the test piece to achieve a better starting position for the measurements. A contamination is still given because structural part and/or test piece has been immersed into the liquid before pressing it. First a whole of diameter 5 mm has been drilled into the test piece as simulated leakage. After fitting the structural part it was coated with PolymerMetal and pressed onto the opening of the test piece. A second overlapping coat with PolymerMetal was not done during the tests. After total curing of the PolymeMetal the bonding was checked by pressure tests:

The attempt to remove the structural part from the test piece by forcible rising of a chisel especially the structural parts were completely destroyed. This is a further indication for the very good bonding of the strcutural parts on the test pieces.

Contact corrosion

There is no direct contact of structural parts of different alloys with the conducting system's surfaces. The metal filled PolymerMetals are electrical non-conductive and can not build a local charge. Therefore there is no contact corrosion possible. Previous examinations were done refering to DIN 50900 in artificial see water and very aggressive moorland with an extreme high moisture from 55% up to 85%.

Purpose of the working method

sealing of leakages at following components:
leakages at any place at liquid carrying metal pipes or containers

sealing of leakages for following liquids:
water, raw, compressor, pneumatic, hydraulic, gear, machine, synthetic oil, petroleum or fuels like benzine, diesel oil, grease products and liquids from the group of alcohols and hydrocarbons

leakage size:
- during tests one or more leakages from size diameter 0,4 mm up to 4 mm on a maximum circle area with diameter 18 mm were sealed successfully
- during tests also cracks with 40 mm length and 0,5 mm width were sealed successfully by using modified structural parts
- during tests also several hair cracks running parallel to each other within an area of 40 mm length and 5 mm width were sealed successfully by using modified structural parts
- during tests also cracks with more than 40 mm length were sealed successfully when several modified structural parts were used

quantity of liquid pouring out before sealing leakage:
at tests a penetration of liquid up to 15 litres/min (at one bigger leakage with diameter 4 mm) or 7 litres/min (at several smaller leakages occuring at the same time) was measured and sealed successfully

pressure of liquid pouring out during sealing leakage:
at tests leakages with pressures from 6 - 10 bar sealed successfully

temperature of liquid pouring out:
at tests leakages with temperatures of pouring liquids from 17 °C to 22 °C were sealed successfully

quick repair method:
leakages are normally sealed within 1 h

Sample pictures of further leakages (klick to zoom)

The new working method's development time has been finished and applied for a patent at the Patent Office. Now the production is in preparation. When you are interested in this new sealing method or in case that you do have any questions or ideas please do not hesitate to get in contact with us.