Bell Furnace Inner Cover Manufacturer in India

Therm process Engineering Pvt. Ltd. manufactures inner covers for bell type annealing furnaces. The inner cover is the sealed stainless steel shell that sits over the charge on the furnace base. It holds the protective atmosphere around the coils while the heating bell fires outside it. Therm process inner covers are fabricated in SS321 in diameters of about 4 to 8 feet and thicknesses of 8 to 20 mm, for service between 500 and 950°C. Share your base diameter, stack height and operating temperature for a replacement quote.

What Is a Bell Furnace Inner Cover?

Bell annealing takes its name from the shape of the furnace. A batch of metal, usually wire or strip coils, is placed on a base assembly. It is enclosed by an inner cover, and the furnace body, or heating bell, is then lowered over the top. Suspended from the crane, the furnace body looks like a bell. The base assembly provides convection, which is the main method of heat transfer to the charge.

The inner cover separates the charge from the heating chamber. Inside it, the protective atmosphere circulates around the coils. Outside it, burners or elements heat the space between the inner cover and the furnace body. The cover must therefore:

• Transfer heat efficiently from the heating bell to the charge
• Stay gas-tight so the protective atmosphere doesn't leak or become contaminated.
• Withstand repeated heating and cooling cycles without cracking, bulging or distorting.

Inner covers are consumables. Thermal cycling eventually causes distortion or cracking, so plants replace them periodically.

Therm process Inner Covers

Therm process fabricates inner covers in SS321, a titanium-stabilised austenitic stainless steel commonly used for elevated-temperature service. Covers are built to suit the customer's base diameter, stack height and sealing arrangement, in diameters of about 4 to 8 ft and wall thicknesses of 8 to 20 mm.

As a furnace manufacturer, Therm process also supplies auto-ignition burners for bell annealing furnaces, and bright annealing and binding wire annealing furnaces. It understands how the inner cover fits into the complete bell annealing system.

Technical Specifications

Benefits of Bell Annealing

According to Thermprocess, bell annealing offers:

• Excellent temperature uniformity
• Consistent product quality
• Good production rates
• Low operating costs

Key Features of Therm process Inner Covers

• SS321 construction for high-temperature cyclic service.
• Sized to your base, from 4 to 8 ft diameter.
• Wall thickness selectable from 8 to 20 mm.
• Rated for 500–950°C operation.
• Made by a bell furnace system supplier.

How the Inner Cover Works in the Bell Annealing Cycle

• Loading Coils are stacked on the base.
• Covering The inner cover is lowered over the stack and sealed to the base.
• Purging Protective atmosphere replaces air inside the cover.
• Heating The heating bell is placed over the inner cover and fired. Heat passes through the cover while base convection circulates the atmosphere.
• Cooling The heating bell is removed and the charge cools under the inner cover, still protected.
• Unloading The inner cover is lifted and the annealed coils are removed.

Applications

• Bell annealing of wire coils
• Bell annealing of strip coils
• Bright annealing under protective atmosphere
• Replacement of worn or distorted inner covers

Industries Served

• Wire drawing and wire products
• Cold-rolled strip processing
• Fastener wire
• Steel processing units with bell annealing lines

Custom Inner Cover Solutions

Share the following:

• Base diameter and sealing arrangement
• Stack height
• Operating temperature
• Existing cover drawing or dimensions
• Quantity required

Why Choose Thermprocess?

• Since 1997, Mumbai.
• Bell annealing system knowledge, including burners and furnaces.
• Fabricated to your base dimensions.
• ISO 9001 & ISO 14001 certified, as stated by the company.

Related Therm process Products

• Bright Annealing Furnace
• Binding Wire Annealing Furnace
• Industrial Burners
• Strand Annealer

Frequently Asked Questions