therelek engineers P.Ltd Peenya, Bangalore, Karnataka

Pit type air circulation furnaces are installed with the opening at ground level or just above it., These are low temperature furnaces with operating temperatures up to 650°C. These furnaces are usually used for heat treatment of non-ferrous alloys, tempering of ferrous alloys after hardening, stress relieving after welding and forming, also for ageing. Since convection is the mode of heat transfer at these temperatures, air circulation is provided inside the retort to maintain stable temperature uniformity.These furnaces are also suitable for controlled atmosphere based processes.

Therelek’s standard pusher type continuous furnace operate up to 1800°C.Higher temperature requirements are also encouraged which require process specific design. A multi-zone control environment is present in continuous high temperature furnaces, often with a single pre-heating zone, followed by multiple heating zones and then cooling zones before exit. Due to the high temperatures involved most of these furnaces operate under controlled and protective atmospheres, with inert gases such as nitrogen and argon used for initial purging, and gas mixtures or gases like cracked ammonia or hydrogen or endogas used to create a suitable atmosphere as per process parameters.

Our standard bogie hearth furnace goes up to 1500°C, however we make custom designed furnaces for any special requirements. High temperature applications are sintering, hardening, annealing and normalizing whereas low temperature applications are tempering and stress relieving. The control system is provided with options to set and control the ramping rate, soaking rate and cooling rate depending on the process cycle, the option of PLC based control is also available. Our Bogie hearth furnace is used in open atmosphere and also in controlled atmosphere as per application. Designs are usually in and out bogie (hearth) movement as well as through and through double door bogie movement is provided for an assembly line or process line. Based on customer requirement, the mode of heating is via electrical heaters, gas fired or oil fired burners.

Our standard bogie hearth furnace goes up to 1500°C, however we make custom designed furnaces for any special requirements. High temperature applications are sintering, hardening, annealing and normalizing whereas low temperature applications are tempering and stress relieving. The control system is provided with options to set and control the ramping rate, soaking rate and cooling rate depending on the process cycle, the option of PLC based control is also available. Our Bogie hearth furnace is used in open atmosphere and also in controlled atmosphere as per application. Designs are usually in and out bogie (hearth) movement as well as through and through double door bogie movement is provided for an assembly line or process line. Based on customer requirement, the mode of heating is via electrical heaters, gas fired or oil fired burners. These furnaces are energy efficient and it is achieved by efficient sealing to prevent undue heat losses and thyristor power controls to limit current consumption.

Pit type sealed retort furnaces are of a cylindrical design vertically erected with a positive sealing mechanism on top in order to contain and preserve heat and atmosphere during a process cycle.The job or charge is loaded into a retort which functions as the chamber of the furnace and the retort is heated externally electrically. Pit furnaces like these are used in general engineering and metallurgical applications for carburizing, nitriding, carbonitriding, nitrocarburizing, hardening, tempering, annealing and also in process industries like coal tar processing, separation of titanium and magnesium from ore etcIn process industries these furnaces can also be used in high pressure applications with temperatures from 800°C to 1200°C and pressure ranging from 400mm water column to 9 bar.Temperature control, fluid dissociation, gas penetration and dosing can all be taken up for automated operation.

A multi-zone control environment is present in continuous high temperature furnace, often with a single pre-heating zone, followed by multiple heating zones and then cooling zones before exit.Due to the high temperatures involved most of these furnaces operate under controlled and protective atmospheres, with inert gases such as nitrogen and argon used for initial purging, and gas mixtures or gases like cracked ammonia or hydrogen or endogas used to create a suitable atmosphere as per process parameters.Specially designed corrugated muffles (metallic) are used to withstand thermal expansion for certain processes.

LTA ovens or low temperature air circulation ovens have a wide area of application from baking ovens to ageing ovens. The ovens can be designed with complete inner stainless steel construction for long life.Adjustable slotted baffles or fixed sturdy baffles ensure an even and uniform flow of air throughout the inside chamber so that desired temperature stability and uniformity is present throughout the heating cycle. In the process of ageing of aluminium for aerospace components, our chamber ovens are built to meet AMS 2750E Standards.

Vacuum furnaces are preferred over conventional methods of heat treatment such as salt bath furnaces and controlled atmosphere furnaces due to the advantages it brings - such as prevention of surface oxidation, decarburization and low distortions on work pieces thus resulting in cleaner surfaces, less rework and less post-heat treatment cleaning or corrective operations.

Our standard bogie hearth furnaces can go up to 1500°C, however any special requirements beyond this can also be taken up with a custom design. High temperature applications include sintering, hardening, annealing and normalizing whereas lower temperature applications include tempering and stress relieving.

Pit type air circulation furnaces are installed with the opening at ground level or just above it. These are low temperature furnaces with operating temperatures up to 650°C. These furnaces are usually used for heat treatment of non-ferrous alloys, tempering of ferrous alloys after hardening, stress relieving after welding and forming, also for ageing.

Lab furnaces used for heat treatment of parts for R & D and testing are made small, compact and exactly as the user defines it. These can be used in labs for developments or as prototypes to be later on implemented on a larger industrial scale.