Expansion Joints

Expansion Joints are in many fields, in railway tracks, piping systems, concrete pouring. Expansion joint is designed to use as these types of expansion joints; Joints in concrete, control joints, thermal expansions, contraction joints, bridge expansion joints. They helps to reduce stresses of movement due accommodating movement to inducing stresses for example with expansion and contraction or cracks in concrete. Some parameters are important, such as joint materials, slab thickness, temperature variations like high temperatures and pressure resistance. In this writing, expansion joints for piping will be discussed.

Expansion joints have been provided for piping and likes in which the end of a length or section of a metal pipe is enlarged, so that it may be telescopically located relative to the end of an adjacent section. The expansion joint between two overlapping sections make the fluid tight by a packing material which usually encircles the inner section and is held in the place between the telescoping sections with a packing gland or a like. Construction permits axial movements between two sections to provide axial expansion of a pipe line under many different climatic or temperature conditions. When expansion joints are used via highly corrosive fluids, which becomes necessary to coat the internal surfaces of both pipe sections and the expansion joints with corrosive resistant materials.

A highly deficient protective coating for metallic pipes’ surfaces will protect them from alkaline or acid corrosive fluids. Comprises a vitreous enamel forms a glass like coating on surfaces to protect when fused thereto. Various techniques are known at the time. These may be applied to metallic surfaces to protect and fuse the thereto by the application of the heat. Usually compositions include fine powdered frit, which is mixed with water so that is a thin coating that may be applied to metal surfaces to be protected. The coating is permitted to dry, by placing in an oven or furnace, so the coating fused to the metallic surface by firing at a usual temperature, usually between twelve hundred and two thousand degrees Fahrenheit.

These skilled about the vitreous enameling art are aware that, is supremely difficult to provide a protection. Vitreous enamel coating, which eliminates the presence of fish scales. That is an enamel defect which appears as a scattered chipping of an enamel from the surface to what was fused and which resembles fish scales. The effect highly affects corrosive resistant qualities of the enamel coatings and many theories have been advanced concerning the cause thereof. Many attentions have been given to provision of an enameling frit or slip. The use of these materials would reduce such defects and minimize their effects.

The defects increase in those instances, where the protective enamel coatings are applied to the both inner and outer surfaces of metallic articles. Ice and particularly in instances where the coatings are applied to the both inner and outer surfaces of a relatively thin walled metal tubes or the likes. Under these kind of conditions, those defects have created disadvantages of that big magnitude which they rendered its impractical to coat the exposed surfaces of the expansion joints of the types heretofore mentioned.

The defects cause in part by gases which are formed in the metals during the subsequent cooling or during the firing process, the escape of these gases either are prevented by the enamel coatings which are causing the lack of adherences. Results in chips in these coatings are called fish scales. That belief is supported by the fact that when the both inner and outer surfaces of a thin walled metal pipe or tubes are coated. The defect is supremely increased over these which occurs when only one of the surfaces of the material is coated.

To overcome this above mentioned disadvantage the new invention fills the provision of an expansion joint of a telescopic type, heretofore mentioned, in which that will not be necessary to coat the inner and the outer surfaces of any metallic walls.

A corrosion resistant expansion joint for pipe lines or the like, comprising a pair of elongated metallic tubular members, one end of a member piece are being telescopically disposed inside the other member piece. An elongate metallic sleeve is extending from the other inner member piece in the reverse overlapping relation to mentioned inner member piece to provide an elongated annular space between the sleeves and the inner member piece with a smooth rounded wall portion that is being disposed between the sleeves and inner member piece as the only physical contact piece between the inner member piece and the sleeve. The outer tubular members are being radially spaced from mentioned sleeves and having a filleted curved inner surfaces approaching the mentioned sleeve and a second curved filleted inner surface which overlying the mentioned sleeve to provide a shoulder role in the mentioned outer member piece is radially removed from the mentioned sleeve. The corrosion resistant packing materials are disposed against the mentioned arenas.

A corrosion resistant expansion joint for the pipe lines and the likes are comprising a pair of metallic tubes. Each tubes are opening to the both ends and the ends of the inner tubes being telescopically arranged within an end of the outer tubes. An elongated metallic sleeve surrounding the telescoping end of the inner tubes. With the inner diameter of the mentioned sleeves are greater than the outer diameters of the inner tubes. Weld means joining to the inner ends of the mentioned inner tubes and the sleeves with the mentioned welds. Which means that the bridging the gaps between the inner ends of the sleeves and the inner tubes to provide a fluid tight expansion joint where between and providing one only physical contact between the inner tubes and the sleeves. The mentioned weld means that having one rounded outer surface to provide a smooth curved juncture between the inner tubes and the outer surfaces of the sleeves, one vitreous enamel coating is extending continuously along the inner surfaces of the inner tubes and around the rounded outer surfaces of the weld means and covering the outer surfaces of the mentioned sleeves. The right opposite end of the mentioned sleeves from the mentioned welds mean being radially spaced from the inner tube whereby gas liberated during the fusing of the enamel to the inner member piece and the mentioned sleeve that may pass freely from the inner surfaces of the sleeves and the outer surfaces of the inner tubes and to escape through the spaces between the sleeves and the inner tubes.


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