GF-ELTI Tangential, Radial or Differential Systems are plants connected to Heat Treatment lines and intended to quench products.
Tangential and Radial Quenching Systems are based on the concept of a quenching shower, in which the product is cooled down through an extinction fluid jet wetting its surface. These systems are characterised by the possibility of directing the extinction fluid so as to impact the product surface tangentially or radially (i.e. perpendicularly). Their main field of application is the one relative to axial-symmetric products since, in this case, it is possible to make use of symmetries and to quench the product simultaneously, from each direction. Typical examples are the sprayers for tubes: nozzles are adjustable according to the processed diameter in the tangential version and they are fixed, i.e. pointing at the tube axis, in the radial version.
In Tangential Quenching Systems, the refrigerant flow is constantly “brushing” the surface of the product to avoid the build-up of static fluid layers (“films”) acting as a thermal insulator between the product and the cold refrigerating fluid (e.g. the water vapour in case of quenching with water shower). At the same time, a continuous cold refrigerating fluid exchange is ensured on the surface to be quenched. Quenching Systems have an extremely drastic quenching effect and offer considerable cooling uniformity. These systems are particularly suitable at the first quenching stages when it is necessary to quickly bring down the temperature of the product to be quenched.
In Radial Quenching Systems, the fluid is impacting the surface of the product perpendicularly. Unlike the Tangential Quenching System, in which the jet is lapping the surface and then moving away, the fluid tends to linger on the surface and to wrap it up in the Radial Quenching System. Radial Quenching Systems are particularly advantageous at the last quenching stage, i.e. when allotropic transformations are completed and the product is required to cool down to achieve the ambient temperature.
These quenching systems are often combined within the same machine; tangential systems are used in a first work step because they can cool down very sharply; at a later time, when cooling gradients are reduced, radial systems are used because they can complete the cooling process at a lower rate.
Differential Quenching Systems are special plants used for quenching in some localised areas of a product only. As a consequence, these systems can put the extinction fluid in contact with the product only in the areas where quenching is required. These plants can use a quenching shower, a quenching bath or a combination of both of them, according to the geometry of the product to be quenched. Typical examples are the wheel treatment tanks where quenching is required on the rolling surface only.
Types of treated products: metal products, mainly but not limited to, axial-symmetric ones (e.g. tubes, wheels, cylinders, etc.).
