Operating heat treatment system, comprises utilizing a part of the heat flow guided into a cooling part of the system by forced convection of a heat treatment product for preheating the treatment product by high convective heat transfer

摘要

The method comprises utilizing a part of the heat flow guided into a cooling part of a heat treatment system by forced convection of a heat treatment product for preheating the heat treatment product by high convective heat transfer of 80 W/(m 2K) before entering into a heating part of the system heated by an external energy supply, and conveying and regulating the mass flow of blowing gases from a circulation ventilator of a cooling zone (21) through a gas line (5) into a last pre-heating zone (13) viewed in a transport direction of the product. The system has heating and cooling parts. The method comprises utilizing a part of the heat flow guided into a cooling part of a heat treatment system by forced convection of a heat treatment product for preheating the heat treatment product by high convective heat transfer of 80 W/(m 2K) before entering into a heating part of the system heated by an external energy supply, and conveying and regulating the mass flow of blowing gases from a circulation ventilator of a cooling zone (21) through a gas line (5) into a last pre-heating zone (13) viewed in a transport direction of the heat treatment product. The heat treatment system comprises the heating part and the cooling part having a high heat exchanger in the cooling part with a heat treatment product by forced convection corresponding to a heat transition coefficient of 80 W/(m 2K) and a movement of the heat treatment product in and through the heating part after carrying out heating from the heating part in and through the cooling part and/or after carrying out cooling from the cooling part. The mass flow of the blowing gases is regulated by using a regulator (7) and a temperature sensor (8) for circulating temperature in the cooling zone, so that the temperature of the blowing gas flow circulating in the cooling zone for product-cooling maintains a predetermined convenient value for heating the treatment gases. The recirculation of the gas mass flow conveyed from the cooling zone into the last pre-heating zone is carried out from a first pre-heating zone into the cooling part viewed in the transport direction of the heat treatment product back to the cooling zone through the gas line from the entrance of the pre-heating part viewed in the transport direction of the heat treatment product. The gas mass flow is kept at same value as in the gas line by using regulators and/or mass flow measuring devices for determining the gas mass flow in the gas lines for the recirculation and in the gas lines for the supply of the gas mass flow. The gas mass flow is conveyed through the gas line by a separate ventilator instead of the circulation ventilator of the cooling zone. The gas mass flow is conveyed back to the cooling part through the gas line by the separate ventilator instead of the circulation ventilator of the concerned pre-heating zone. A heat transport fluid heats up with the circulating gas in the cooling part through the heat flow withdrawn to the heat treatment product, is conveyed in the pre-heating part by using a pipeline and a conveyor, is cooled during preheating the heat treatment product introduced in the pre-heating part and again back flows through the pipeline into the cooling part. The heat transport fluid cycle is regulated by the regulators, so that the temperature of the blowing gases in the cooling part is kept to the determined convenient value for heating the heat transport fluid.