Heat treatment unit for vacuum insulated tubing (VIT)
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The scheme of the convective circulation furnace with full heat exchange cycle (heating, holding and cooling) for elongated products heat treatment has been developed. This furnace operates in the mode of periodic change in the direction of the flow to the opposite . In order to intensify the process of cooling the products by effective supply and remove of the coolant from the working area such furnaces use reversing flow devices, which consist of two centrifugal fans, one of them operates in the mode of aerodynamic locking of the coolant. The experimental control characteristics of reverse flow devices, assembled on the basis of various types of centrifugal fans, are presented. The data obtained can be used in the development of convective circulation furnaces with full heat exchange cycle.

On the basis of this technology, OJSC VNIIMT has developed, manufactured and put into operation a heating unit for vacuum insulated tubings (VIT) for JSC Sinarsky Pipe Plant, Kamensk-Uralsky, Russia.

The unit is designed for heating and cooling a package of 6 vacuum insulated tubings with outer diameters of 89-245 mm and a length of 10-12m with the possibility of simultaneous vacuuming process of the annular space.

The productivity and quality of the pipes being processed are achieved due to the VIT uniform heating and cooling technology developed at OJSC VNIIMT with the possibility of changing the direction of the heat transfer agent to the opposite.

The main specifications of heat resistant fans are the following:
• Fan capacity 25000-38000 m3/h;
• Total pressure under normal conditions up to 3000 Pa;
• Maximum temperature of transmitted medium up to 450 C˚;
• Motor power 55 kW.

Heat treatment unit equipped with two heat resistant circulating fans

Heat treatment unit equipped with two heat resistant circulating fans 

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