US 4,225,121 A · Energy efficient heat-treating furnace system

Abstract

A method and apparatus are disclosed for heat-treating parts in a furnace system which uses a minimum total amount of energy. The self-contained, continuous heat-treating system includes components such as a carburizer, a tempering furnace, and a part cooler. Energy transfer between these and other components operable at different temperatures and/or energy requirements are used to maximize thermal efficiency of the system. Furnace components are provided and interconnected so that combustion air for radiant tube heaters supplying thermal energy to parts in a high temperature furnace such as a carburizer is preheated by exchanging heat in a part cooler and by recuperation of the carburizer exhaust; combustion products from the carburizer supply energy for reheating parts in a lower temperature furnace such as a tempering furnace; the tempering furnace exhaust is used for preheating parts prior to their entry into the carburizer; and energy transferred by the parts to a quench medium is used to heat water for subsequent washing of the parts. In one arrangement of components a tempering furnace is mounted on top of a carburizer as part of a compact multi-level configuration. In another arrangement the components form a single level system with energy transfer features and high thermal efficiencies similar to those of the multi-level system.

Claims13

Dependent claims

A furnace system for heat-treating parts comprising:

a first furnace;
a preheater for heating parts prior to entry of the parts into said first furnace;
heater means for heating parts to a predetermined temperature in said first furnace;
a quench unit connected to the part discharge end of said first furnace, said quench unit containing a quench medium for rapidly lowering the temperature of parts received from said first furnace;
a second furnace for heating parts to a lower temperature than said predetermined temperature following passage of said parts through said quench unit;
a cooler attached to the part discharge end of said second furnace for cooling parts received from said second furnace and heating air for use as combustion air in said heater means;
means for directing said heated air from said cooler to said heater means;
means for directing the products of combustion of said heater means from said first furnace through said second furnace for heating of parts in said second furnace;
means for directing the exhaust of said second furnace through said preheater for heating of parts therein;
and
transport means for moving said parts successively through said preheater, said first furnace, said quench unit, said second furnace, and said cooler.

8 more elements

Dependencies are inferred from the claim text.

Energy efficient heat-treating furnace system

Life of this patent

Energy efficient heat-treating furnace system

Life of this patent

Abstract

Claims13